Making (Impure) Sulfuric Acid from Household Ingredients

Since my most viewed blog post was on making hydrochloric acid from household ingredients, maybe you want to know how to make sulfuric acid too.  Very well.  But first you have to make the hydrochloric acid.  The link below tells you how to do that:

http://amedleyofpotpourri.blogspot.com/2011/12/making-hydrochloric-acid-from-household.html


OK, you're ready to convert hydrochloric into sulfuric acid.  To do this, you need a source of the sulfate anion (SO₄^2-), Two possibilities come to mind: the best one is epsom salts, which is just magnesium sulfate (MgSO₄); the other is gypsum, a mineral made from calcium sulfate (CaSO₄).

I'll assume you use the epsom salts. First you need to drive the water out of the salts, which is part of its chemical composition and makes up about half its mass. I haven't actually done this, but what should work is strongly heating the salts, then measuring its mass (since you haven't got a balance in your kitchen you'll have to improvise). However you do it, keep repeating the process until the mass doesn't drop any further – evidence that all the water has been indeed driven from the now anhydrous magnesium sulfate.

How much of the dried sulfate do you need? I estimate a decent ballpark figure of half the amount of salt and sodium bicarbonate you used to make the hydrochloric acid. So, if you start with a mass of epsom salts twice that, it whould get dried down to the amount of anhydrous MgSO₄ you'll need. 
Then – dissolve that mass into the hydrochloric acid (if everything is done just exactly right, it will all go into solution) – and presto! – you've got your sulfuric acid. The only thing wrong is that it also contains magnesium chloride (MgCl₂) in the the solution. If you want to concentrate the mixture into strong or pure sulfuric acid (BE VERY CAREFUL), you'll have to boil the water completely away. Pure sulfuric acid has a texture like glycerin and can be slightly yellow. Don't forget that you've still got the magnesium chloride in it – I'm uncertain of the chemistry that could happen here (well, it won't explode, I can tell you that) – nor can I come up with a means of removing it off the top of my head.

The pertinent chemistry is:

MgSO₄ + 2 HCl -----> MgCl₂ + H₂SO₄

Actually, both compounds exist as ionic species in solution:

Mg²⁺ + SO₄^2- + H⁺ + 2 Cl^- + HSO₄^-

And there you have it, you brave souls with the hearts of curious children. Enjoy!