Children's rights

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Children%27s_rights

Children's rights or the rights of children are a subset of human rights with particular attention to the rights of special protection and care afforded to minors. The 1989 Convention on the Rights of the Child (CRC) defines a child as "any human being below the age of eighteen years, unless under the law applicable to the child, majority is attained earlier." Children's rights includes their right to association with both parents, human identity as well as the basic needs for physical protection, food, universal state-paid education, health care, and criminal laws appropriate for the age and development of the child, equal protection of the child's civil rights, and freedom from discrimination on the basis of the child's race, gender, sexual orientation, gender identity, national origin, religion, disability, color, ethnicity, or other characteristics.

Interpretations of children's rights range from allowing children the capacity for autonomous action to the enforcement of children being physically, mentally and emotionally free from abuse, though what constitutes "abuse" is a matter of debate. Other definitions include the rights to care and nurturing. There are no definitions of other terms used to describe young people such as "adolescents", "teenagers", or "youth" in international law, but the children's rights movement is considered distinct from the youth rights movement. The field of children's rights spans the fields of law, politics, religion, and morality.

Justifications

A boy working as a "clock boy" on the streets of Merida, Mexico

[There] is a mass of human rights law, both treaty and 'soft law', both general and child-specific, which recognises the distinct status and particular requirements of children. [Children], owing to their particular vulnerability and their significance as the future generation, are entitled to special treatment generally, and, in situations of danger, to priority in the receipt of assistance and protection.

— Jenny Kuper, International Law Concerning Child Civilians in Armed Conflict (1997, Clarendon Press)

As minors by law, children do not have autonomy or the right to make decisions on their own for themselves in any known jurisdiction of the world. Instead their adult caregivers, including parents, social workers, teachers, youth workers, and others, are vested with that authority, depending on the circumstances. Some believe that this state of affairs gives children insufficient control over their own lives and causes them to be vulnerable. Louis Althusser has gone so far as to describe this legal machinery, as it applies to children, as "repressive state apparatuses".

Structures such as government policy have been held by some commentators to mask the ways adults abuse and exploit children, resulting in child poverty, lack of educational opportunities, and child labour. On this view, children are to be regarded as a minority group towards whom society needs to reconsider the way it behaves.

Researchers have identified children as needing to be recognized as participants in society whose rights and responsibilities need to be recognized at all ages.

Historic definitions of children's rights

Pharaoh's daughter having pity on baby Moses in the floating basket. (The Hebrew babies had been ordered killed by her father.)

Sir William Blackstone (1765-9) recognized three parental duties to the child: maintenance, protection, and education. In modern language, the child has a right to receive these from the parent.

The League of Nations adopted the Geneva Declaration of the Rights of the Child (1924), which enunciated the child's right to receive the requirements for normal development, the right of the hungry child to be fed, the right of the sick child to receive health care, the right of the backward child to be reclaimed, the right of orphans to shelter, and the right to protection from exploitation.

The United Nations Universal Declaration of Human Rights (1948) in Article 25(2) recognized the need of motherhood and childhood to "special protection and assistance" and the right of all children to "social protection".

The United Nations General Assembly adopted the United Nations Declaration of the Rights of the Child (1959), which enunciated ten principles for the protection of children's rights, including the universality of rights, the right to special protection, and the right to protection from discrimination, among other rights.

Consensus on defining children's rights has become clearer in the last fifty years. A 1973 publication by Hillary Clinton (then an attorney) stated that children's rights were a "slogan in need of a definition". According to some researchers, the notion of children's rights is still not well defined, with at least one proposing that there is no singularly accepted definition or theory of the rights held by children.

Children's rights law is defined as the point where the law intersects with a child's life. That includes juvenile delinquency, due process for children involved in the criminal justice system, appropriate representation, and effective rehabilitative services; care and protection for children in state care; ensuring education for all children regardless of their race, gender, sexual orientation, gender identity, national origin, religion, disability, color, ethnicity, or other characteristics, and; health care and advocacy.

Classification

Children have two types of human rights under international human rights law. They have the same fundamental general human rights as adults, although some human rights, such as the right to marry, are dormant until they are of age, Secondly, they have special human rights that are necessary to protect them during their minority. General rights operative in childhood include the right to security of the person, to freedom from inhuman, cruel, or degrading treatment, and the right to special protection during childhood. Particular human rights of children include, among other rights, the right to life, the right to a name, the right to express his views in matters concerning the child, the right to freedom of thought, conscience and religion, the right to health care, the right to protection from economic and sexual exploitation, and the right to education.

Children's rights are defined in numerous ways, including a wide spectrum of civil, political, economic, social and cultural rights. Rights tend to be of two general types: those advocating for children as autonomous persons under the law and those placing a claim on society for protection from harms perpetrated on children because of their dependency. These have been labeled as the right of empowerment and as the right to protection.

United Nations educational guides for children classify the rights outlined in the Convention on the Rights of the Child as the "3 Ps": Provision, Protection, and Participation. They may be elaborated as follows:

• Provision: Children have the right to an adequate standard of living, health care, education and services, and to play and recreation. These include a balanced diet, a warm bed to sleep in, and access to schooling.
• Protection: Children have the right to protection from abuse, neglect, exploitation and discrimination. This includes the right to safe places for children to play; constructive child rearing behavior, and acknowledgment of the evolving capacities of children.
• Participation: Children have the right to participate in communities and have programs and services for themselves. This includes children's involvement in libraries and community programs, youth voice activities, and involving children as decision-makers.

In a similar fashion, the Child Rights International Network (CRIN) categorizes rights into two groups:

• Economic, social and cultural rights, related to the conditions necessary to meet basic human needs such as food, shelter, education, health care, and gainful employment. Included are rights to education, adequate housing, food, water, the highest attainable standard of health, the right to work and rights at work, as well as the cultural rights of minorities and indigenous peoples.
• Environmental, cultural and developmental rights, which are sometimes called "third generation rights", and including the right to live in safe and healthy environments and that groups of people have the right to cultural, political, and economic development.

Amnesty International openly advocates four particular children's rights, including the end to juvenile incarceration without parole, an end to the recruitment of military use of children, ending the death penalty for people under 21, and raising awareness of human rights in the classroom. Human Rights Watch, an international advocacy organization, includes child labour, juvenile justice, orphans and abandoned children, refugees, street children and corporal punishment.

Scholarly study generally focuses children's rights by identifying individual rights. The following rights "allow children to grow up healthy and free":

• Freedom of speech
• Freedom of thought
• Freedom from fear
• Freedom of choice and the right to make decisions
• Ownership over one's body

Physical rights

A report by the Committee on Social Affairs, Health, and Sustainable Development of the Parliamentary Assembly of the Council of Europe identified several areas the Committee was concerned about, including procedures such as "female genital mutilation, the circumcision of young boys for religious reasons, early childhood medical interventions in the case of intersex children and the submission to or coercion of children into piercings, tattoos or plastic surgery". The Assembly adopted a non-binding resolution in 2013 that calls on its 47 member-states to take numerous actions to promote the physical integrity of children.

Article 19 of the Convention on the Rights of the Child enjoins parties to "take all appropriate legislative, administrative, social and educational measures to protect the child from all forms of physical or mental violence, injury or abuse, neglect or negligent treatment, maltreatment or exploitation". The Committee on the Rights of the Child interprets article 19 as prohibiting corporal punishment, commenting on the "obligation of all States Party to move quickly to prohibit and eliminate all corporal punishment." The United Nations Human Rights Committee has also interpreted Article 7 of the International Covenant on Civil and Political Rights prohibiting "cruel, inhuman or degrading treatment or punishment" to extend to children, including corporal punishment of children.

Newell (1993) argued that "...pressure for protection of children's physical integrity should be an integral part of pressure for all children's rights."

The Committee on Bioethics of the American Academy of Pediatrics (AAP) (1997), citing the Convention on the Rights of the Child (1989), asserts that "every child should have the opportunity to grow and develop free from preventable illness or injury."

Intersex rights

The standard medical model was medical falsification for intersex children, from textbook 1963.

Main articles: Intersex human rights and Intersex genital mutilation

Intersex children are children born or develop, atypical sexual traits. Historically intersex children have been the subject of involuntary surgical assignment and later hormone replacement therapy to a binary sex/gender, which was often concealed from patients; in the US, this system was known as the optimum gender of rearing model, which organizations such as the ISNA heavily criticized. Intersex children often face high levels of mental stress, and stigmatization, as well as isolation for having atypical bodies, or undergoing medical procedures.

The World Health Organization standard of care for intersex children is to delay all surgery until the child is old enough to participate in informed consent, unless emergency surgery is needed. Intersex people are likewise more likely to develop gender dysphoria then the general population. Organizations such as InterACT and intersex civil society groups exist to support and advocate for intersex youth, and stop involuntary unnecessary medicalization and shame surrounding intersex subjects.

Other issues

Other issues affecting children's rights include the military use of children, sale of children, child prostitution and child pornography.

Difference between children's rights and youth rights

Main article: Youth rights

In the majority of jurisdictions, for instance, children are not allowed to vote, to marry, to buy alcohol, to have sex, or to engage in paid employment. Within the youth rights movement, it is believed that the key difference between children's rights and youth rights is that children's rights supporters generally advocate the establishment and enforcement of protection for children and youths, while youth rights (a far smaller movement) generally advocates the expansion of freedom for children and/or youths and of rights such as suffrage.

Parents' rights and responsibilities

Parents' rights and Right to family life are connected with Parental responsibilities. Parents are given sufficient powers to fulfill their duties to the child.

Parents affect the lives of children in a unique way, and as such their role in children's rights has to be distinguished in a particular way. Particular issues in the child-parent relationship include child neglect, child abuse, freedom of choice, corporal punishment and child custody. There have been theories offered that provide parents with rights-based practices that resolve the tension between "commonsense parenting" and children's rights. The issue is particularly relevant in legal proceedings that affect the potential emancipation of minors, and in cases where children sue their parents.

A child's rights to a relationship with both their parents is increasingly recognized as an important factor for determining the best interests of the child in divorce and child custody proceedings. Some governments have enacted laws creating a rebuttable presumption that shared parenting is in the best interests of children.

Limitations of parental powers

Parents do not have absolute power over their children. Parents are subject to criminal laws against abandonment, abuse, and neglect of children. International human rights law provides that manifestation of one's religion may be limited in the interests of public safety, for the protection of public order, health or morals, or for the protection of the rights and freedoms of others.

Courts have placed other limits on parental powers and acts. The Supreme Court of the United States, in the case of Prince v. Massachusetts, ruled that a parent's religion does not permit a child to be placed at risk. The Lords of Appeal in Ordinary ruled, in the case of Gillick v West Norfolk and Wisbech Area Health Authority and another, that parents' rights diminish with the increasing age and competency of the child, but do not vanish completely until the child reaches majority. Parents' rights are connected to the parent's duties to the child. In the absence of duty, no parents' rights exists. The Supreme Court of Canada ruled, in the case of E (Mrs) v Eve, that parents may not grant surrogate consent for non-therapeutic sterilization. The Supreme Court of Canada has ruled, in the case of B. (R.) v. Children's Aid Society of Metropolitan Toronto:

While children undeniably benefit from the Charter, most notably in its protection of their rights to life and to the security of their person, they are unable to assert these rights, and our society accordingly presumes that parents will exercise their freedom of choice in a manner that does not offend the rights of their children.

Adler (2013) argues that parents are not empowered to grant surrogate consent for non-therapeutic circumcision of children.

Movement

Main article: Children's rights movement

See also: Timeline of young people's rights in the United Kingdom and Timeline of young people's rights in the United States

The 1796 publication of Thomas Spence's Rights of Infants is among the earliest English-language assertions of the rights of children. Throughout the 20th century, children's rights activists organized for homeless children's rights and public education. The 1927 publication of The Child's Right to Respect by Janusz Korczak strengthened the literature surrounding the field, and today dozens of international organizations are working around the world to promote children's rights. In the UK the formation of a community of educationalists, teachers, youth justice workers, politicians and cultural contributors called the New Ideals in Education Conferences (1914–37) stood for the value of 'liberating the child' and helped to define the 'good' primary school in England until the 80s. Their conferences inspired the UNESCO organisation, the New Education Fellowship.

A.S. Neill's 1915 book A Dominie's Log (1915), a diary of a headteacher changing his school to one based on the liberation and happiness of the child, can be seen as a cultural product that celebrates the heroes of this movement.

Opposition

The opposition to children's rights long predates any current trend in society, with recorded statements against the rights of children dating to the 13th century and earlier. Opponents to children's rights believe that young people need to be protected from the adultcentric world, including the decisions and responsibilities of that world. In a dominantly adult society, childhood is idealized as a time of innocence, a time free of responsibility and conflict, and a time dominated by play. The majority of opposition stems from concerns related to national sovereignty, states' rights, the parent-child relationship. Financial constraints and the "undercurrent of traditional values in opposition to children's rights" are cited, as well. The concept of children's rights has received little attention in the United States.

International human rights law

Further information: International child abduction

Main article: Declaration of the Rights of the Child

The Universal Declaration of Human Rights is seen as a basis for all international legal standards for children's rights today. There are several conventions and laws that address children's rights around the world. A number of current and historical documents affect those rights, including the Declaration of the Rights of the Child, drafted by Eglantyne Jebb in 1923, endorsed by the League of Nations in 1924 and reaffirmed in 1934. A slightly expanded version was adopted by the United Nations in 1946, followed by a much expanded version adopted by the General Assembly in 1959. It later served as the basis for the Convention on the Rights of the Child.

International Covenant on Civil and Political Rights

The United Nations adopted the International Covenant on Civil and Political Rights (ICCPR) in 1966. The ICCPR is a multilateral international covenant that has been ratified or acceded to by nearly all nations on Earth. Nations which have become state-parties to the Covenant are required to honor and enforce the rights enunciated by the Covenant. The treaty came into effect on 23 March 1976. The rights codified by the ICCPR are universal, so they apply to everyone without exception and this includes children. Although children have all rights, some rights such as the right to marry and the right to vote come into effect only after the child reaches maturity.

Some general rights applicable to children include:

• the right to life
• the right to security of person
• the right to freedom from torture
• the right to freedom from cruel, inhuman or degrading treatment or punishment
• the right to be separated from adults when charged with a crime, the right to speedy adjudication, and the right to be accorded treatment appropriate to their age

Article 24 codifies the right of the child to special protection due to his minority, the right to a name, and the right to a nationality.

Convention on the Rights of the Child

Main article: Convention on the Rights of the Child

The United Nations' 1989 Convention on the Rights of the Child, or CRC, is the first legally binding international instrument to incorporate the full range of human rights—civil, cultural, economic, political and social rights. Its implementation is monitored by the Committee on the Rights of the Child. National governments that ratify it commit themselves to protecting and ensuring children's rights, and agree to hold themselves accountable for this commitment before the international community. The CRC is the most widely ratified human rights treaty with 196 ratifications; the United States is the only country not to have ratified it.

The CRC is based on four core principles: the principle of non-discrimination; the best interests of the child; the right to life, survival and development; and considering the views of the child in decisions that affect them, according to their age and maturity. The CRC, along with international criminal accountability mechanisms such as the International Criminal Court, the Yugoslavia and Rwanda Tribunals, and the Special Court for Sierra Leone, is said to have significantly increased the profile of children's rights worldwide.

Vienna Declaration and Programme of Action

The Vienna Declaration and Programme of Action urges, at Section II para 47, all nations to undertake measures to the maximum extent of their available resources, with the support of international cooperation, to achieve the goals in the World Summit Plan of Action. And calls on States to integrate the Convention on the Rights of the Child into their national action plans. By means of these national action plans and through international efforts, particular priority should be placed on reducing infant and maternal mortality rates, reducing malnutrition and illiteracy rates and providing access to safe drinking water and basic education. Whenever so called for, national plans of action should be devised to combat devastating emergencies resulting from natural disasters and armed conflicts and the equally grave problem of children in extreme poverty. Further, para 48 urges all states, with the support of international cooperation, to address the acute problem of children under especially difficult circumstances. Exploitation and abuse of children should be actively combated, including by addressing their root causes. Effective measures are required against female infanticide, harmful child labour, sale of children and organs, child prostitution, child pornography, and other forms of sexual abuse. This influenced the adoptions of Optional Protocol on the Involvement of Children in Armed Conflict and Optional Protocol on the Sale of Children, Child Prostitution and Child Pornography.

Enforcement

A variety of enforcement organizations and mechanisms exist to ensure children's rights. They include the Child Rights Caucus for the United Nations General Assembly Special Session on Children. It was set up to promote full implementation and compliance with the Convention on the Rights of the Child, and to ensure that child rights were given priority during the UN General Assembly Special Session on Children and its Preparatory process. The United Nations Human Rights Council was created "with the hope that it could be more objective, credible and efficient in denouncing human rights violations worldwide than the highly politicized Commission on Human Rights." The NGO Group for the Convention on the Rights of the Child is a coalition of international non-governmental organizations originally formed in 1983 to facilitate the implementation of the United Nations Convention on the Rights of the Child.

National law

Many countries around the world have children's rights ombudspeople or children's commissioners whose official, governmental duty is to represent the interests of the public by investigating and addressing complaints reported by individual citizens regarding children's rights. Children's ombudspeople can also work for a corporation, a newspaper, an NGO, or even for the general public.

United States law

Further information: Timeline of young people's rights in the United States, International child abduction in the United States, and Child labor laws in the United States

The United States has signed but not ratified the CRC. As a result, children's rights have not been systematically implemented in the U.S.

Children are generally afforded the basic rights embodied by the Constitution, as enshrined by the Fourteenth Amendment to the United States Constitution. The Equal Protection Clause of that amendment is to apply to children, born within a marriage or not, but excludes children not yet born. This was reinforced by the landmark US Supreme Court decision of In re Gault (1967). In this trial 15-year-old Gerald Gault of Arizona was taken into custody by local police after being accused of making an obscene telephone call. He was detained and committed to the Arizona State Industrial School until he reached the age of 21 for making an obscene phone call to an adult neighbor. In an 8–1 decision, the Court ruled that in hearings which could result in commitment to an institution, people under the age of 18 have the right to notice and counsel, to question witnesses, and to protection against self-incrimination. The Court found that the procedures used in Gault's hearing met none of these requirements.

The Supreme Court of the United States ruled in the case of Tinker v. Des Moines Independent Community School District (1969) that students in school have Constitutional rights.

The Supreme Court of the United States has ruled in the case of Roper v. Simmons that persons may not be executed for crimes committed when below the age of eighteen. It ruled that such executions are cruel and unusual punishment, so they are a violation of the Eighth Amendment to the United States Constitution.

There are other concerns in the United States regarding children's rights. The American Academy of Adoption Attorneys is concerned with children's rights to a safe, supportive and stable family structure. Their position on children's rights in adoption cases states that, "children have a constitutionally based liberty interest in the protection of their established families, rights which are at least equal to, and we believe outweigh, the rights of others who would claim a 'possessory' interest in these children." Other issues raised in American children's rights advocacy include children's rights to inheritance in same-sex marriages and particular rights for youth.

German law

A report filed by the President of the INGO Conference of the Council of Europe, Annelise Oeschger finds that children and their parents are subject to United Nations, European Union and UNICEF human rights violations. Of particular concern is the German (and Austrian) agency, Jugendamt (German: Youth office) that often unfairly allows for unchecked government control of the parent-child relationship, which have resulted in harm including torture, degrading, cruel treatment and has led to children's death. The problem is complicated by the nearly "unlimited power" of the Jugendamt officers, with no processes to review or resolve inappropriate or harmful treatment. By German law, Jugendamt (JA) officers are protected against prosecution. JA officers span of control is seen in cases that go to family court where experts testimony may be overturned by lesser educated or experienced JA officers; In more than 90% of the cases the JA officer's recommendation is accepted by family court. Officers have also disregarded family court decisions, such as when to return children to their parents, without repercussions. Germany has not recognized related child-welfare decisions made by the European Parliamentary Court that have sought to protect or resolve children and parents' rights violations.

Addictive personality

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Addictive_personality

An addictive personality refers to a hypothesized set of personality traits that make an individual predisposed to developing addictions. This hypothesis states that there may be common personality traits observable in people suffering from addiction; however, the lack of a universally agreed upon definition has marked the research surrounding addictive personality. Addiction is a fairly broad term; it is most often associated with substance use disorders, but it can also be extended to cover a number of other compulsive behaviors, including sex, internet, television, gambling, food, and shopping. Within these categories of addiction a common diagnostic scale involves tolerance, withdrawal, and cravings. This is a fairly contentious topic, with many experts suggesting the term be retired due to a lack of cumulative evidence supporting the existence of addictive personality. It has been claimed that characteristics of personality attributed to addictive personality do not predict addiction, but rather can be the result of addiction. However, different personality traits have been linked to various types of addictive behaviors, suggesting that individual addictions may be associated with different personality profiles. The strongest consensus is that genetic factors play the largest role in determining a predisposition for addictive behaviors. Even then, however, genes play different roles in different types of addictions. Forty to seventy percent of the population variance in the expression of addictions can be explained by genetic factors.

Etiology

The following factors are believed to influence addiction susceptibility.

Psychological factors

• Impulsivity
• Sensation seeking
• Nonconformity combined with weak commitment to socially valued goals for achievement
• Social alienation and tolerance for deviance
• Heightened stress coupled with lack of coping skills.

Some claim the existence of "addictive beliefs" in people more likely to develop addictions, such as "I cannot make an impact on my world" or "I am not good enough", which may lead to developing traits associated with addiction, such as depression and emotional insecurity. People who strongly believe that they control their own lives and are mostly self-reliant in learning information (rather than relying on others) are less likely to become addicted. However, it is unclear whether these traits are causes, results or merely associated coincidentally. For example, depression due to physical disease can cause feelings of hopelessness that are mitigated after successful treatment of the underlying condition, and addiction can increase dependence on others. Certain psychological disorders such as panic attacks, depressive disorders, and generalized anxiety disorder have been related to addiction. The addicted person, who struggles with reality and feels negative feelings, such as anxiety and depression, will seek out ways to help them avoid such feelings.

Food addiction

Overeating due to food addiction has not yet been recognized as a medical disorder under the Diagnostic and Statistical Manual of Mental Disorders despite its prevalence in the general population. A study based on social cognitive theories, included a personality-targeted intervention that was shown to help treat substance addiction. It is feasible that by changing certain elements of one's personality, one can gain a step in the right direction towards changing their addictive personality.

Genetic factors

According to David Goldman, a prominent alcoholism researcher, addiction is one of the behavioral disorders most strongly correlated with genetic makeup. Individual traits can share common underlying factors or interact. For example, depression, poor self-control, and compulsive behavior are linked to neurotransmitter abnormalities, i.e., biological mechanisms. In laboratory studies with rats, only some rats develop a pattern of self-administration of stimulant drugs, supporting the existence of some inherent propensity for addictive tendencies. In these rats, a positive correlation was found between locomotor response to novel stimuli and the amount of amphetamine self-administered during the first few days of testing. Twin and adoption studies have shown genetic factors account for 50–60% of the risk for alcoholism. In early adolescence, social and familial factors play a more important role in the initiation of drug use, but their importance fades with progression into adulthood. The gene CHRNA5 has been heavily linked to the addictions of cigarettes. Researchers discovered that the CHRNA5 variant creates a less nauseating experience for a first time smoker. The gene is active in the region of the brain called the habenula. Research showed that frequent smoking might damage the neurons within the habenula that inhibit its role in aversion and avoidance, which might cause the smoker to then use more nicotine to feel relief from resulting distressful and negative feelings.

Environmental factors

Studies have found numerous environmental factors that correlate with addiction. Exposure to sustained stress in childhood, such as physical or sexual abuse, especially accompanied by unpredictable parental behavior strongly correlates with drug addiction and overeating in adulthood. Children who tend to react to distress in a more rash way have been linked to becoming more likely to drink and smoke in their adolescence. Results from this research found that this was because the reaction to distress affected psychosocial learning, which led to increased expectancy to drink or smoke. A lack of social interaction has also been shown to correlate with addictive tendencies; rats reared in isolation were quicker to develop a pattern of cocaine self-administration than rats reared in groups. There is a gene/environment connection in that individuals with particular personality traits may self-select into different environments, e.g., they may seek out work environments where addictive substances are more readily available.

Description

Addiction can be defined as an excessive amount of time and resources spent in engaging in an activity or an experience that somehow affects the person's quality of life. An addictive personality is when those addictive behaviors progress and change as the individual seeks to produce the desired mood.

People that face this issue are currently defined to have a brain disease as promoted by the National Institute on Drug Abuse and other authorities. People who experience addictive personality disorders typically act on impulses and cannot deal with delayed gratification. At the same time, people with this type of personality tend to believe that they do not fit into societal norms and therefore, acting on impulses, deviate from conformity to rebel. People with addictive personalities are very sensitive to emotional stress. They have trouble handling situations that they deem frustrating, even if the event is for a very short duration. The combination of low self-esteem, impulsivity and low tolerance for stress causes these individuals to have frequent mood swings and often suffer from some sort of depression. A coping mechanism to deal with their conflicting personality becomes their addiction and the addiction acts as something that the person can control when they find it difficult to control their personality traits.

People with addictive personalities typically switch from one addiction to the next. These individuals may show impulsive behavior such as excessive caffeine consumption, Internet use, eating chocolate or other sugar-laden foods, television watching, or even running.

Extraversion, self-monitoring, and loneliness are also common characteristics found in those who suffer from addiction. Individuals who score high on self-monitoring are more prone to developing an addiction. High self-monitors are sensitive to social situations; they act how they think others expect them to act. They wish to fit in, hence they are very easily influenced by others. Likewise, those who have low self-esteem also seek peer approval; therefore, they participate in "attractive" activities such as smoking or drinking to try to fit in.

People with addictive personalities find it difficult to manage their stress levels. In fact, lack of stress tolerance is a telltale sign of the disorder. They find it difficult to face stressful situations and fight hard to get out of such conditions. Long-term goals prove difficult to achieve because people with addictive personalities usually focus on the stress that comes with getting through the short-term goals. Such personalities will often switch to other enjoyable activities the moment that they are deprived of enjoyment in their previous addiction.

Addictive individuals feel highly insecure when it comes to relationships. They may often find it difficult to make commitments in relationships or trust their beloved because of the difficulty they find in achieving long-term goals. They constantly seek approval of others and as a result, these misunderstandings may contribute to the destruction of relationships. People suffering from addictive personality disorder usually undergo depression and anxiety, managing their emotions by developing addiction to alcohol, other types of drugs, or other pleasurable activities.

An addict is more prone to depression, anxiety, and anger. Both the addict's environment, genetics and biological tendency contribute to their addiction. People with very severe personality disorders are more likely to become addicts. Addictive substances usually stop primary and secondary neuroses, meaning people with personality disorders like the relief from their pain.

Personality traits and addiction

Addiction is defined by scholars as "a biopsychosocial disorder characterized by persistent use of drugs (including alcohol) despite substantial harm and adverse consequences". Substance-based addictions are those based upon the release of dopamine in the brain, upon which the range of sensations produced by the euphoric event in the brain changes the brain's immediate behavior, causing more susceptibility for future addictions. Behavior-based addictions, on the other hand, are those that are not linked to neurological behavior as much and are thus thought to be linked to personality traits; it is this type of addiction that combines a behavior with a mental state and the repeated routine is therefore associated with the mental state.

Drug addiction

A group of British forensic psychologists and data scientists analysed a new large database of users of psychoactive substances. To analyse the predisposition to drug use, they utilized 7 psychological traits, the Five Factor Model supplemented by Impulsivity and Sensation seeking:

• N Neuroticism is a long-term tendency to experience negative emotions such as nervousness, tension, anxiety and depression (associated adjectives: anxious, self-pitying, tense, touchy, unstable, and worrying);
• E Extraversion is manifested in outgoing, warm, active, assertive, talkative, cheerful characters, often in search of stimulation (associated adjectives: active, assertive, energetic, enthusiastic, outgoing, and talkative);
• O Openness to experience is a general appreciation for art, unusual ideas, and imaginative, creative, unconventional, and wide interests (associated adjectives: artistic, curious, imaginative, insightful, original, and wide interest);
• A Agreeableness is a dimension of interpersonal relations, characterized by altruism, trust, modesty, kindness, compassion and cooperativeness (associated adjectives: appreciative, forgiving, generous, kind, sympathetic, and trusting);
• C Conscientiousness is a tendency to be organized and dependable, strong-willed, persistent, reliable, and efficient (associated adjectives: efficient, organized, reliable, responsible, and thorough);
• Imp Impulsivity is defined as a tendency to act without adequate forethought;
• SS Sensation Seeking is defined by the search for experiences and feelings, that are varied, novel, complex and intense, and by the readiness to take risks for the sake of such experiences.

These factors are not statistically independent but the condition number of the correlation matrix is less than 10 and the multicollinearity effects are not expected to be strong.

The results of the detailed analysis of modern data support partially the hypothesis about psychological predisposition to addiction. The group of users of illicit drugs differs from the group of non-users for N, O, A, C, Imp, and SS. Symbolically, this difference can be illustrated as follows:

${\displaystyle \mathrm{N}\Uparrow ,\mathrm{O}\Uparrow ,\mathrm{A}\Downarrow ,\mathrm{C}\Downarrow ,\mathrm{I}\mathrm{m}\mathrm{p}\Uparrow ,\mathrm{S}\mathrm{S}\Uparrow }$

(N, O, Imp, and SS scores are higher for users; A and C scores are lower for users).

The hypothesis about importance of E for addiction was not supported by this aggregated analysis of use of all illicit drugs.

Analysis of consumption of different drugs separately demonstrated that predisposition to use of different drugs is different. For all illicit drugs groups of their users have the following common properties:

${\displaystyle \mathrm{O}\Uparrow ,\mathrm{C}\Downarrow ,\mathrm{I}\mathrm{m}\mathrm{p}\Uparrow ,\mathrm{S}\mathrm{S}\Uparrow }$

(O, Imp, and SS scores are higher for users and C score is lower for users).

Deviation of N, E, and A scores for users of different drugs can be different. For example, heroin users have average profile

${\displaystyle \mathrm{N}\Uparrow ,\mathrm{E}\Downarrow ,\mathrm{O}\Uparrow ,\mathrm{A}\Downarrow ,\mathrm{C}\Downarrow ,\mathrm{I}\mathrm{m}\mathrm{p}\Uparrow ,\mathrm{S}\mathrm{S}\Uparrow ,}$

whereas for LSD and Ecstasy (the latter being a so-called "Party drug") users N has no significant deviation from the population level and E can be higher.

Several personality profiles of risky behaviour were identified by various researchers, for example ${\displaystyle \mathrm{N}\Uparrow ,\mathrm{C}\Downarrow }$ (Insecures) and ${\displaystyle \mathrm{E}\Uparrow ,\mathrm{C}\Downarrow }$(Impulsives, Hedonists). Various types of addictive personality have in common low C.

Internet addiction

Internet addiction is associated with higher scores in neuroticism and lower scores in extraversion and conscientiousness. One explanation for the association with high neuroticism is that virtual environments may be regarded as more safe and comfortable by individuals with lower self-esteem and increased negative emotion (traits associated with high neuroticism) compared to real-life environments. Similarly, individuals with low extraversion that desire social interaction but are averse to face-to-face interaction may find the opportunity for online communication attractive.

Personality theories of addiction

Personality theories of addiction are psychological models that associate personality traits or modes of thinking (i.e., affective states) with an individual's proclivity for developing an addiction. Models of addiction risk that have been proposed in psychology literature include an affect dysregulation model of positive and negative psychological affects, the reinforcement sensitivity theory model of impulsiveness and behavioral inhibition, and an impulsivity model of reward sensitization and impulsiveness.

Controversy

There is an ongoing debate about the question of whether an addictive personality really exists. The assumption that personality might be to blame for an addicted person, who is in need of rehabilitation due to drug and alcohol addictions, can have great negative impacts from its supporting a homogeneous answer to a heterogeneous issue in question. These people run the risk of being labeled as stigmas and become incorrectly marginalized, and these misjudgments of personality may then lead to poor mental, medical, and social health practices. There are two sides of this argument, each with many levels and variations. One side believes that there are certain traits and dimensions of personality that, if existent in a person, cause the person to be more prone to developing addictions throughout their life. The other side argues that addiction is in chemistry, as in how the brain's synapses respond to neurotransmitters and is therefore not affected by personality. A major argument in favor of defining and labeling an addictive personality has to do with the human ability to make decisions and the notion of free will. This argument suggests human beings are aware of their actions and what the consequences of their own actions are and many choose against certain things because of this. This can be seen in that people are not forced to drink excessively or smoke every day, but it is within the reach of their own free will that some may choose to do so.^[42] Therefore, those with addictive personalities are high in neuroticism and hence choose to engage in riskier behaviors. The theory of addictive personalities agrees that there are two types of people: risk-takers and risk-averse. Risk-takers enjoy challenges, new experiences and want instant gratification. These people enjoy the excitement of danger and trying new things. On the other hand, risk-averse are those who are by nature cautious in what they do and the activities they involve themselves in. It is the personality traits of individuals that combine to create either a risk-taker or risk-averse person.

Another important concern is the lack of evidence supporting the addictive personality label and the possibility of stigma. While there is a medical consensus surrounding the genetic components of addiction, there is no such consensus supporting the idea that specific personality types have a tendency towards addictive behaviors. In fact, continued use of this term in the absence of clear evidence could be damaging to the people who believe they have an addictive personality.

pH

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/PH

Test tubes containing solutions of pH 1–10 colored with an indicator

Acids and bases
Acceptor number Acid Acid–base reaction Acid–base homeostasis Acid strength Acidity function Amphoterism Base Buffer solutions Dissociation constant Donor number Equilibrium chemistry Extraction Hammett acidity function pH Proton affinity Self-ionization of water Titration Lewis acid catalysis Frustrated Lewis pair Chiral Lewis acid ECW model
Acid types
Brønsted–Lowry Lewis Mineral Organic Oxide Strong Superacids Weak Solid
Base types
Brønsted–Lowry Lewis Organic Oxide Strong Superbases Non-nucleophilic Weak
v t e

In chemistry, pH (/piːˈeɪtʃ/ pee-AYCH), also referred to as acidity or basicity, historically denotes "potential of hydrogen" (or "power of hydrogen"). It is a logarithmic scale used to specify the acidity or basicity of aqueous solutions. Acidic solutions (solutions with higher concentrations of hydrogen (H⁺) ions) are measured to have lower pH values than basic or alkaline solutions.

The pH scale is logarithmic and inversely indicates the activity of hydrogen ions in the solution

${\displaystyle \text{pH}=-{\log }_{10}(a_{{\text{H}}^{+}})\approx -{\log }_{10}([{\text{H}}^{+}])}$

where [H⁺] is the equilibrium molar concentration of H⁺ (in M = mol/L) in the solution. At 25 °C (77 °F), solutions of which the pH is less than 7 are acidic, and solutions of which the pH is greater than 7 are basic. Solutions with a pH of 7 at 25 °C are neutral (i.e. have the same concentration of H⁺ ions as OH⁻ ions, i.e. the same as pure water). The neutral value of the pH depends on the temperature and is lower than 7 if the temperature increases above 25 °C. The pH range is commonly given as zero to 14, but a pH value can be less than 0 for very concentrated strong acids or greater than 14 for very concentrated strong bases.

The pH scale is traceable to a set of standard solutions whose pH is established by international agreement. Primary pH standard values are determined using a concentration cell with transference by measuring the potential difference between a hydrogen electrode and a standard electrode such as the silver chloride electrode. The pH of aqueous solutions can be measured with a glass electrode and a pH meter or a color-changing indicator. Measurements of pH are important in chemistry, agronomy, medicine, water treatment, and many other applications.

History

In 1909, the Danish chemist Søren Peter Lauritz Sørensen introduced the concept of pH at the Carlsberg Laboratory, originally using the notation "p_H•", with H• as a subscript to the lowercase p. The concept was later revised in 1924 to the modern pH to accommodate definitions and measurements in terms of electrochemical cells.

For the sign p, I propose the name 'hydrogen ion exponent' and the symbol p_H•. Then, for the hydrogen ion exponent (p_H•) of a solution, the negative value of the Briggsian logarithm of the related hydrogen ion normality factor is to be understood.

Sørensen did not explain why he used the letter p, and the exact meaning of the letter is still disputed. Sørensen described a way of measuring pH using potential differences, and it represents the negative power of 10 in the concentration of hydrogen ions. The letter p could stand for the French puissance, German Potenz, or Danish potens, all meaning "power", or it could mean "potential". All of these words start with the letter p in French, German, and Danish, which were the languages in which Sørensen published: Carlsberg Laboratory was French-speaking; German was the dominant language of scientific publishing; Sørensen was Danish. He also used the letter q in much the same way elsewhere in the paper, and he might have arbitrarily labelled the test solution "p" and the reference solution "q"; these letters are often paired with e4 then e5. Some literature sources suggest that "pH" stands for the Latin term pondus hydrogenii (quantity of hydrogen) or potentia hydrogenii (power of hydrogen), although this is not supported by Sørensen's writings.

In modern chemistry, the p stands for "the negative decimal logarithm of", and is used in the term pK_a for acid dissociation constants, so pH is "the negative decimal logarithm of H⁺ ion concentration", while pOH is "the negative decimal logarithm of OH⁻ ion concentration".

Bacteriologist Alice Catherine Evans, who influenced dairying and food safety, credited William Mansfield Clark and colleagues, including herself, with developing pH measuring methods in the 1910s, which had a wide influence on laboratory and industrial use thereafter. In her memoir, she does not mention how much, or how little, Clark and colleagues knew about Sørensen's work a few years prior. She said:

In these studies [of bacterial metabolism] Dr. Clark's attention was directed to the effect of acid on the growth of bacteria. He found that it is the intensity of the acid in terms of hydrogen-ion concentration that affects their growth. But existing methods of measuring acidity determined the quantity, not the intensity, of the acid. Next, with his collaborators, Dr. Clark developed accurate methods for measuring hydrogen-ion concentration. These methods replaced the inaccurate titration method of determining the acid content in use in biologic laboratories throughout the world. Also they were found to be applicable in many industrial and other processes in which they came into wide usage.

The first electronic method for measuring pH was invented by Arnold Orville Beckman, a professor at the California Institute of Technology in 1934. It was in response to a request from the local citrus grower Sunkist, which wanted a better method for quickly testing the pH of lemons they were picking from their nearby orchards.

Definition

pH

The pH of a solution is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, a_H+. Mathematically, pH is expressed as:

${\displaystyle \text{pH}=-{\log }_{10}(a_{{\text{H}}^{+}})={\log }_{10}\left(\frac{1}{a_{{\text{H}}^{+}}}\right)}$

For example, for a solution with a hydrogen ion activity of 5×10⁻⁶ mol/L (i.e., the concentration of hydrogen ions), the pH of the solution can be calculated as follows:

${\displaystyle \text{pH}=-{\log }_{10}(5\times {10}^{-6})=5.3}$

The concept of pH was developed because ion-selective electrodess, which are used to measure pH, respond to activity. The electrode potential, E, follows the Nernst equation for the hydrogen ion, which can be expressed as:

${\displaystyle E=E^0+\frac{RT}{F}\ln (a_{{\text{H}}^{+}})=E^0-\frac{RT\ln 10}{F}\text{pH}\approx E^0-\frac{2.303RT}{F}\text{pH}}$

where E is a measured potential, E⁰ is the standard electrode potential, R is the molar gas constant, T is the thermodynamic temperature, F is the Faraday constant. For H⁺, the number of electrons transferred is one. The electrode potential is proportional to pH when pH is defined in terms of activity.

The precise measurement of pH is presented in International Standard ISO 31-8 as follows: A galvanic cell is set up to measure the electromotive force (e.m.f.) between a reference electrode and an electrode sensitive to the hydrogen ion activity when they are both immersed in the same aqueous solution. The reference electrode may be a silver chloride electrode or a calomel electrode, and the hydrogen-ion selective electrode is a standard hydrogen electrode.

Reference electrode | concentrated solution of KCl || test solution | H₂ | Pt

Firstly, the cell is filled with a solution of known hydrogen ion activity and the electromotive force, E_S, is measured. Then the electromotive force, E_X, of the same cell containing the solution of unknown pH is measured.

${\displaystyle \text{pH}(\text{X})=\text{pH}(\text{S})+\frac{E_{\text{S}}-E_{\text{X}}}{z}}$

The difference between the two measured electromotive force values is proportional to pH. This method of calibration avoids the need to know the standard electrode potential. The proportionality constant, 1/z, is ideally equal to ${\displaystyle \frac{F}{RT\ln 10}}$, the "Nernstian slope".

In practice, a glass electrode is used instead of the cumbersome hydrogen electrode. A combined glass electrode has an in-built reference electrode. It is calibrated against Buffer solutions of known hydrogen ion (H⁺) activity proposed by the International Union of Pure and Applied Chemistry (IUPAC). Two or more buffer solutions are used in order to accommodate the fact that the "slope" may differ slightly from ideal. To calibrate the electrode, it is first immersed in a standard solution, and the reading on a pH meter is adjusted to be equal to the standard buffer's value. The reading from a second standard buffer solution is then adjusted using the "slope" control to be equal to the pH for that solution. Further details, are given in the IUPAC recommendations. When more than two buffer solutions are used the electrode is calibrated by fitting observed pH values to a straight line with respect to standard buffer values. Commercial standard buffer solutions usually come with information on the value at 25 °C and a correction factor to be applied for other temperatures.

The pH scale is logarithmic and therefore pH is a dimensionless quantity.

p[H]

This was the original definition of Sørensen in 1909, which was superseded in favor of pH in 1924. [H] is the concentration of hydrogen ions, denoted [H⁺] in modern chemistry. More correctly, the thermodynamic activity of H⁺ in dilute solution should be replaced by [H⁺]/c₀, where the standard state concentration c₀ = 1 mol/L. This ratio is a pure number whose logarithm can be defined.

It is possible to measure the concentration of hydrogen ions directly using an electrode calibrated in terms of hydrogen ion concentrations. One common method is to titrate a solution of known concentration of a strong acid with a solution of known concentration of strong base in the presence of a relatively high concentration of background electrolyte. By knowing the concentrations of the acid and base, the concentration of hydrogen ions can be calculated and the measured potential can be correlated with concentrations. The calibration is usually carried out using a Gran plot. This procedure makes the activity of hydrogen ions equal to the numerical value of concentration.

The glass electrode (and other Ion selective electrodes) should be calibrated in a medium similar to the one being investigated. For instance, if one wishes to measure the pH of a seawater sample, the electrode should be calibrated in a solution resembling seawater in its chemical composition.

The difference between p[H] and pH is quite small, and it has been stated that pH = p[H] + 0.04. However, it is common practice to use the term "pH" for both types of measurement.

pOH

Relation between pH and pOH. Red represents the acidic region. Blue represents the basic region.

pOH is sometimes used as a measure of the concentration of hydroxide ions, OH⁻. By definition, pOH is the negative logarithm (to the base 10) of the hydroxide ion concentration (mol/L). pOH values can be derived from pH measurements and vice-versa. The concentration of hydroxide ions in water is related to the concentration of hydrogen ions by

${\displaystyle [{\text{OH}}^{-}]=\frac{K_{\text{W}}}{[{\text{H}}^{+}]}}$

where K_W is the self-ionization constant of water. Taking Logarithms,

${\displaystyle \text{pOH}=\text{p}{K}_{\text{W}}-\text{pH}.}$

So, at room temperature, pOH ≈ 14 − pH. However this relationship is not strictly valid in other circumstances, such as in measurements of soil alkalinity.

Measurement

pH Indicators

Average pH of common solutions
Substance	pH range	Type
Battery acid	< 1	Acid
Gastric acid	1.0–1.5
Vinegar	2–3
Orange juice	3.3–4.2
Black coffee	5–5.03
Milk	6.5–6.8
Pure water at 25 °C	7	Neutral
Sea water	7.5–8.4	Base
Ammonia	11.0–11.5
Bleach	12.5
Lye	14

Main article: pH indicator

pH can be measured using indicators, which change color depending on the pH of the solution they are in. By comparing the color of a test solution to a standard color chart, the pH can be estimated to the nearest whole number. For more precise measurements, the color can be measured using a colorimeter or spectrophotometer. A Universal indicator is a mixture of several indicators that can provide a continuous color change over a range of pH values, typically from about pH 2 to pH 10. Universal indicator paper is made from absorbent paper that has been impregnated with a universal indicator. An alternative method of measuring pH is using an electronic pH meter, which directly measures the voltage difference between a pH-sensitive electrode and a reference electrode.

Non-aqueous solutions

pH values can be measured in non-aqueous solutions, but they are based on a different scale from aqueous pH values because the standard states used for calculating hydrogen ion concentrations (activities) are different. The hydrogen ion activity, a_H⁺, is defined as:

${\displaystyle a_{{\text{H}}^{+}}=\exp \left(\frac{{\mu }_{{\text{H}}^{+}}-{\mu }_{{\text{H}}^{+}}^{\ominus }}{RT}\right)}$

where μ_H⁺ is the chemical potential of the hydrogen ion, ${\displaystyle {\mu }_{{\text{H}}^{+}}^{\ominus }}$ is its chemical potential in the chosen standard state, R is the molar gas constant and T is the thermodynamic temperature. Therefore, pH values on the different scales cannot be compared directly because of differences in the solvated proton ions, such as lyonium ions, which require an insolvent scale that involves the transfer activity coefficient of hydronium/lyonium ion.

pH is an example of an acidity function, but others can be defined. For example, the Hammett acidity function, H₀, has been developed in connection with Superacids.

Unified absolute pH scale

In 2010, a new approach to measuring pH was proposed, called the unified absolute pH scale. This approach allows for a common reference standard to be used across different solutions, regardless of their pH range. The unified absolute pH scale is based on the absolute chemical potential of the proton, as defined by the Lewis acid–base theory. This scale applies to liquids, gases, and even solids. The advantages of the unified absolute pH scale include consistency, accuracy, and applicability to a wide range of sample types. It is precise and versatile because it serves as a common reference standard for pH measurements. However, implementation efforts, compatibility with existing data, complexity, and potential costs are some challenges.

Extremes of pH measurements

"Negative pH" redirects here. For the band, see Negative pH (band).

The measurement of pH can become difficult at extremely acidic or alkaline conditions, such as below pH 2.5 (ca. 0.003 mol/dm³ acid) or above pH 10.5 (above ca. 0.0003  mol/dm³ alkaline). This is due to the breakdown of the Nernst equation in such conditions when using a glass electrode. Several factors contribute to this problem. First, liquid junction potentials may not be independent of pH. Second, the high ionic strength of concentrated solutions can affect the electrode potentials. At high pH the glass electrode may be affected by "alkaline error", because the electrode becomes sensitive to the concentration of cations such as Na⁺ and K⁺ in the solution. To overcome these problems, specially constructed electrodes are available.

Runoff from mines or mine tailings can produce some extremely low pH values, down to −3.6.

Applications

Pure water has a pH of 7 at 25 °C, meaning it is neutral. When an acid is dissolved in water, the pH will be less than 7, while a base, or alkali, will have a pH greater than 7. A strong acid, such as hydrochloric acid, at concentration 1 mol dm⁻³ has a pH of 0, while a strong alkali like sodium hydroxide, at the same concentration, has a pH of 14. Since pH is a logarithmic scale, a difference of one in pH is equivalent to a tenfold difference in hydrogen ion concentration.

Neutrality is not exactly 7 at 25 °C, but 7 serves as a good approximation in most cases. Neutrality occurs when the concentration of hydrogen ions ([H⁺]) equals the concentration of hydroxide ions ([OH⁻]), or when their activities are equal. Since self-ionization of water holds the product of these concentration [H⁺] × [OH⁻] = K_w, it can be seen that at neutrality [H⁺] = [OH⁻] = √K_w, or pH = pK_w/2. pK_w is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers of both ions. However the pH of the neutral NaCl solution will be slightly different from that of neutral pure water because the hydrogen and hydroxide ions' activity is dependent on ionic strength, so K_w varies with ionic strength.

When pure water is exposed to air, it becomes mildly acidic. This is because water absorbs carbon dioxide from the air, which is then slowly converted into bicarbonate and hydrogen ions (essentially creating carbonic acid).

CO
₂+ H
₂O ⇌ HCO⁻
₃+ H⁺

pH in soil

See also: Soil pH

Nutritional elements availability within soil varies with pH. Light blue color represents the ideal range for most plants.

The United States Department of Agriculture Natural Resources Conservation Service, formerly Soil Conservation Service classifies soil pH ranges as follows:

Denomination	pH range
Ultra acidic	< 3.5
Extremely acidic	3.5–4.4
Very strongly acidic	4.5–5.0
Strongly acidic	5.1–5.5
Moderately acidic	5.6–6.0
Slightly acidic	6.1–6.5
Neutral	6.6–7.3
Slightly alkaline	7.4–7.8
Moderately alkaline	7.9–8.4
Strongly alkaline	8.5–9.0
Very strongly alkaline	9.0–10.5
Hyper alkaline	> 10.5

Topsoil pH is influenced by soil parent material, erosional effects, climate and vegetation. A recent map of topsoil pH in Europe shows the alkaline soils in Mediterranean, Hungary, East Romania, North France. Scandinavian countries, Portugal, Poland and North Germany have more acid soils.

pH in plants

Lemon juice tastes sour because it contains 5% to 6% citric acid and has a pH of 2.2 (high acidity).

Plants contain pH-dependent pigments that can be used as pH indicators, such as those found in hibiscus, red cabbage (anthocyanin), and grapes (red wine). Citrus fruits have acidic juice primarily due to the presence of citric acid, while other carboxylic acids can be found in various living systems. The protonation state of phosphate derivatives, including ATP, is pH-dependent. Hemoglobin, an oxygen-transport enzyme, is also affected by pH in a phenomenon known as the Root effect.

pH in the ocean

See also: Seawater § pH value, Ocean § pH and alkalinity, and Ocean acidification

The pH of seawater plays an important role in the ocean's carbon cycle. There is evidence of ongoing ocean acidification (meaning a drop in pH value): Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide (CO₂) levels exceeding 410 ppm (in 2020). CO₂ from the atmosphere is absorbed by the oceans. This produces carbonic acid (H₂CO₃) which dissociates into a bicarbonate ion (HCO⁻
₃) and a hydrogen ion (H⁺). The presence of free hydrogen ions (H⁺) lowers the pH of the ocean.

Three pH scales in oceanography

The measurement of pH in seawater is complicated by the chemical properties of seawater, and three distinct pH scales exist in chemical oceanography. In practical terms, the three seawater pH scales differ in their pH values up to 0.10, differences that are much larger than the accuracy of pH measurements typically required, in particular, in relation to the ocean's carbonate system. Since it omits consideration of sulfate and fluoride ions, the free scale is significantly different from both the total and seawater scales. Because of the relative unimportance of the fluoride ion, the total and seawater scales differ only very slightly.

As part of its operational definition of the pH scale, the IUPAC defines a series of Buffer solutions across a range of pH values (often denoted with National Bureau of Standards (NBS) or National Institute of Standards and Technology (NIST) designation). These solutions have a relatively low ionic strength (≈ 0.1) compared to that of seawater (≈&mnsp;0.7), and, as a consequence, are not recommended for use in characterizing the pH of seawater, since the ionic strength differences cause changes in electrode potential. To resolve this problem, an alternative series of buffers based on artificial seawater was developed. This new series resolves the problem of ionic strength differences between samples and the buffers, and the new pH scale is referred to as the total scale, often denoted as pH_T. The total scale was defined using a medium containing sulfate ions. These ions experience protonation, H⁺ + SO²⁻
₄↔ HSO⁻
₄, such that the total scale includes the effect of both protons (free hydrogen ions) and hydrogen sulfate ions:

[H⁺]_T = [H⁺]_F + [HSO⁻
₄]

An alternative scale, the free scale, often denoted pH_F, omits this consideration and focuses solely on [H⁺]_F, in principle making it a simpler representation of hydrogen ion concentration. Only [H⁺]_T can be determined, therefore [H⁺]_F must be estimated using the [SO²⁻
₄] and the stability constant of HSO⁻
₄, K^*
_S:

[H⁺]_F = [H⁺]_T − [HSO⁻
₄] = [H⁺]_T ( 1 + [SO²⁻
₄] / K^*
_S )⁻¹

However, it is difficult to estimate K^*
_S in seawater, limiting the utility of the otherwise more straightforward free scale.

Another scale, known as the seawater scale, often denoted pH_SWS, takes account of a further protonation relationship between hydrogen ions and fluoride ions, H⁺ + F⁻ ⇌ HF. Resulting in the following expression for [H⁺]_SWS:

[H⁺]_SWS = [H⁺]_F + [HSO⁻
₄] + [HF]

However, the advantage of considering this additional complexity is dependent upon the abundance of fluoride in the medium. In seawater, for instance, sulfate ions occur at much greater concentrations (> 400 times) than those of fluoride. As a consequence, for most practical purposes, the difference between the total and seawater scales is very small.

The following three equations summarize the three scales of pH:

pH_F = −log₁₀[H⁺]_F

pH_T = −log₁₀([H⁺]_F + [HSO⁻
₄]) = −log₁₀[H⁺]_T

pH_SWS = −log₁₀(H⁺]_F + [HSO⁻
₄] + [HF]) = −log₁₀[v]_SWS

pH in food

The pH level of food influences its flavor, texture, and shelf life. Acidic foods, such as citrus fruits, tomatoes, and vinegar, typically have a pH below 4.6 with sharp and tangy taste, while basic foods taste bitter or soapy. Maintaining the appropriate pH in foods is essential for preventing the growth of harmful microorganisms. The alkalinity of vegetables such as spinach and kale can also influence their texture and color during cooking. The pH also influences the Maillard reaction, which is responsible for the browning of food during cooking, impacting both flavor and appearance.

pH of various body fluids

pH of various body fluids

Compartment	pH
Gastric acid	1.5–3.5
Lysosomes	4.5
Human skin	4.7
Granules of chromaffin cells	5.5
Urine	6.0
Breast milk	7.0–7.45
Cytosol	7.2
Blood (natural pH)	7.34–7.45
Cerebrospinal fluid (CSF)	7.5
Mitochondrial matrix	7.5
Pancreas secretions	8.1

In living organisms, the pH of various Body fluids, cellular compartments, and organs is tightly regulated to maintain a state of acid-base balance known as acid–base homeostasis. Acidosis, defined by blood pH below 7.35, is the most common disorder of acid–base homeostasis and occurs when there is an excess of acid in the body. In contrast, alkalosis is characterized by excessively high blood pH.

Blood pH is usually slightly basic, with a pH of 7.365, referred to as physiological pH in biology and medicine. Plaque formation in teeth can create a local acidic environment that results in tooth decay through demineralization. Enzymes and other Proteins have an optimal pH range for function and can become inactivated or denatured outside this range.

pH calculations

When calculating the pH of a solution containing acids and/or bases, a chemical speciation calculation is used to determine the concentration of all chemical species present in the solution. The complexity of the procedure depends on the nature of the solution. Strong acids and bases are compounds that are almost completely dissociated in water, which simplifies the calculation. However, for weak acids, a quadratic equation must be solved, and for weak bases, a cubic equation is required. In general, a set of non-linear simultaneous equations must be solved.

Water itself is a weak acid and a weak base, so its dissociation must be taken into account at high pH and low solute concentration (see Amphoterism). It dissociates according to the equilibrium

2 H₂O ⇌ H₃O⁺ (aq) + OH⁻ (aq)

with a dissociation constant, K_w defined as

${\displaystyle K_{\text{w}}=[{\text{H}}^{+}][{\text{OH}}^{-}]}$

where [H⁺] stands for the concentration of the aqueous hydronium ion and [OH⁻] represents the concentration of the hydroxide ion. This equilibrium needs to be taken into account at high pH and when the solute concentration is extremely low.

Strong acids and bases

Strong acids and bases are compounds that are essentially fully dissociated in water. This means that in an acidic solution, the concentration of hydrogen ions (H+) can be considered equal to the concentration of the acid. Similarly, in a basic solution, the concentration of hydroxide ions (OH-) can be considered equal to the concentration of the base. The pH of a solution is defined as the negative logarithm of the concentration of H⁺, and the pOH is defined as the negative logarithm of the concentration of OH⁻. For example, the pH of a 0.01 in moles per litreM solution of hydrochloric acid (HCl) is equal to 2 (pH = −log₁₀(0.01)), while the pOH of a 0.01 M solution of sodium hydroxide (NaOH) is equal to 2 (pOH = −log₁₀(0.01)), which corresponds to a pH of about 12.

However, self-ionization of water must also be considered when concentrations of a strong acid or base is very low or high. For instance, a 5×10⁻⁸ M solution of HCl would be expected to have a pH of 7.3 based on the above procedure, which is incorrect as it is acidic and should have a pH of less than 7. In such cases, the system can be treated as a mixture of the acid or base and water, which is an amphoteric substance. By accounting for the self-ionization of water, the true pH of the solution can be calculated. For example, a 5×10⁻⁸ M solution of HCl would have a pH of 6.89 when treated as a mixture of HCl and water. The self-ionization equilibrium of solutions of sodium hydroxide at higher concentrations must also be considered.

Weak acids and bases

A weak acid or the conjugate acid of a weak base can be treated using the same formalism.

• Acid HA: HA ⇌ H⁺ + A⁻
• Base A: HA⁺ ⇌ H⁺ + A

First, an acid dissociation constant is defined as follows. Electrical charges are omitted from subsequent equations for the sake of generality

${\displaystyle K_a=\frac{[\text{H}][\text{A}]}{[\text{HA}]}}$

and its value is assumed to have been determined by experiment. This being so, there are three unknown concentrations, [HA], [H⁺] and [A⁻] to determine by calculation. Two additional equations are needed. One way to provide them is to apply the law of mass conservation in terms of the two "reagents" H and A.

${\displaystyle C_{\text{A}}=[\text{A}]+[\text{HA}]}$

${\displaystyle C_{\text{H}}=[\text{H}]+[\text{HA}]}$

C stands for analytical concentration. In some texts, one mass balance equation is replaced by an equation of charge balance. This is satisfactory for simple cases like this one, but is more difficult to apply to more complicated cases as those below. Together with the equation defining K_a, there are now three equations in three unknowns. When an acid is dissolved in water C_A = C_H = C_a, the concentration of the acid, so [A] = [H]. After some further algebraic manipulation an equation in the hydrogen ion concentration may be obtained.

${\displaystyle [\text{H}{]}^2+K_a[\text{H}]-K_a{C}_a=0}$

Solution of this quadratic equation gives the hydrogen ion concentration and hence p[H] or, more loosely, pH. This procedure is illustrated in an ICE table which can also be used to calculate the pH when some additional (strong) acid or alkaline has been added to the system, that is, when C_A ≠ C_H.

For example, what is the pH of a 0.01 M solution of benzoic acid, pK_a = 4.19?

• Step 1: ${\displaystyle K_a={10}^{-4.19}=6.46\times {10}^{-5}}$
• Step 2: Set up the quadratic equation. ${\displaystyle [\text{H}{]}^2+6.46\times {10}^{-5}[\text{H}]-6.46\times {10}^{-7}=0}$
• Step 3: Solve the quadratic equation. ${\displaystyle [{\text{H}}^{+}]=7.74\times {10}^{-4};\mathrm{p}\mathrm{H}=3.11}$

For alkaline solutions, an additional term is added to the mass-balance equation for hydrogen. Since the addition of hydroxide reduces the hydrogen ion concentration, and the hydroxide ion concentration is constrained by the self-ionization equilibrium to be equal to ${\displaystyle \frac{K_w}{[{\text{H}}^{+}]}}$, the resulting equation is:

${\displaystyle C_{\text{H}}=\frac{[\text{H}]+[\text{HA}]-K_w}{[\text{H}]}}$

General method

Some systems, such as with polyprotic acids, are amenable to spreadsheet calculations. With three or more reagents or when many complexes are formed with general formulae such as A_pB_qH_r, the following general method can be used to calculate the pH of a solution. For example, with three reagents, each equilibrium is characterized by an equilibrium constant, β.

${\displaystyle [{\text{A}}_p{\text{B}}_q{\text{H}}_r]={\beta }_{pqr}[\text{A}{]}^p[\text{B}{]}^q[\text{H}{]}^r}$

Next, write down the mass-balance equations for each reagent:

${\displaystyle \begin{array}{rl}{C}_{\text{A}}& =[\text{A}]+\mathrm{\Sigma }p{\beta }_{pqr}[\text{A}{]}^p[\text{B}{]}^q[\text{H}{]}^r\\ C_{\text{B}}& =[\text{B}]+\mathrm{\Sigma }q{\beta }_{pqr}[\text{A}{]}^p[\text{B}{]}^q[\text{H}{]}^r\\ C_{\text{H}}& =[\text{H}]+\mathrm{\Sigma }r{\beta }_{pqr}[\text{A}{]}^p[\text{B}{]}^q[\text{H}{]}^r-K_w[\text{H}{]}^{-1}\end{array}}$

There are no approximations involved in these equations, except that each stability constant is defined as a quotient of concentrations, not activities. Much more complicated expressions are required if activities are to be used.

There are three simultaneous equations in the three unknowns, [A], [B] and [H]. Because the equations are non-linear and their concentrations may range over many powers of 10, the solution of these equations is not straightforward. However, many computer programs are available which can be used to perform these calculations. There may be more than three reagents. The calculation of hydrogen ion concentrations, using this approach, is a key element in the determination of equilibrium constants by potentiometric titration.