Electrochemistry

schi_zo SG

For an aq electrolyte e.g. CuSO4(aq) and both electrodes are inert, which half eqns do you use occuring at anode?

4OH- --> O2 + 2H2O + 4e- redox pot is -0.40

or 2H20 --> O2 + 4H+ + 4e- redox pot is -1.23

My friend told me not to use 4OH- ions because aq solution does not mean there is abundant H+ ions or OH- ions, so H2O half eqn is used instead.

He told me acidified solution then able to use H+ ions. RIGHT OR WRONG? im confused..

dkcx SG

U not in NS meh why asking chemistry questions now?

schi_zo SG

my friend is in NS but not me. I am lazy to create an account so..

dkcx SG

my friend is in NS but not me. I am lazy to create an account so..

Wakao, create an account juz need an email u also lazy. I think typing a question requires more work than that...

I also lazy think of the answer then...

UltimaOnline SG

Both are acceptable at ‘O’ and ‘A’ level exams.

However, for the sake of technical accuracy, it makes better chemistry sense to use water as the species oxidized (and/or reduced) in aqueous solutions, as it’s molarity far exceeds that of OH- ions (or H+ ions). Unless the solution is acidic (then H+ rather than water, is reduced at the cathode) or alkaline (then OH- rather than water, is oxidized at the anode).

schi_zo SG

Thanks for clearing my doubts!!