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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: knowlege is power on August 25, 2005, 06:36:03 AM

Title: Making Sulphuric acid
Post by: knowlege is power on August 25, 2005, 06:36:03 AM

I have been thinking would it be posible to make relativley pure H₂SO₄ by electrolysing a solution of copper(II) sulphate, using graphite of some other unreactive material for the electrodes. These are the reactions that i think happen.
CuSO₄ + H₂O => Cu²⁺_(aq) + SO₄^2-_(aq)
cathode: Cu²⁺_(aq) + 2e^- => Cu_(s)

anode: 2SO₄^2-_(aq) => 2SO₃ + 4e^- + O_2(g)
Then,
SO₃ + H₂O => H₂SO_4(aq)
If any one could tell me if this is right it woud be much apreciated
(before any one starts laughing atconsider the fact that im only 17 and my chem techer makes more mistakes than i do) :-\

Title: Re:Making Sulphuric acid
Post by: xiankai on August 25, 2005, 09:14:58 AM

the reaction 4OH- --> 2H2O + O2 + 4e- has a lower reduction potential than 2SO42- --> 2SO3 + 4e-

so the former will take place instead of the latter.

Title: Re:Making Sulphuric acid
Post by: knowlege is power on August 25, 2005, 09:03:16 PM

so are you saying that i wont work, or it will but i just stuffed up my eqautions

Title: Re:Making Sulphuric acid
Post by: jdurg on August 25, 2005, 10:27:00 PM

He's saying that instead of the SO4(2-) going to SO3(g), the OH- ions which are always present in solution will be converted into water and oxygen gas, so you won't get any SO3(g) produced.