Thread: Question

I have one question which was asked in one of the olympiads.
Which of the following is/are the product(s) of electrolysis of aqueos CuSo4?
A SO2 & O2, B Only Cu, C Only O2, Both B and C

Since the copper sulphate will dissociate into copper ions and sulphate ions, with the copper ions likley deposited on the cathode, we are left with sulphate ions moving to the anode. Logically they would further dissociate into sulphur dioxide and oxygen. So it looks like B) and c) are correct.

Warning: I haven't done any chemistry for for three or four decades, so I wouldn't bet a million dollars on this.

well that's enough for me i knew that cuso4 disassociates into cu and so4 ions but it's further disassociation....

I would tell the same. B and C.
the stakes get better

It's only Cu.

In the reaction setup you'd have an anode of pure copper, and you'd electroplate copper on the cathode during the reaction. The concentration of copper sulfate stays the same during the whole reaction (for every atom of Cu you deposit on the surface of the cathode, another one is ionised into solution from the anode). Thus, the reaction finishes when the anode has been completely eaten away.

I am too agreed with you matt. I have too studied that on electrolysing it would give the products: Cu but it also give so4 ions. But there has been no such option in the question.
Well I think it's a ticky one. It's answer is Cu since in the question it has been specified product(s)

Mat is certainly right when using Cu electrodes. But when using inert electrodes H2O will be oxidised at the anode (it’s been a while, but I think this is the case).

2 H2O --> O2 + 4 H(+) + 4 e(-)

Maybe anand_kapadia could tell us if the electrodes were given in the question?

No they were not mentioned in the question. I copied the question as it was.
I agree with what you said. It is certainly due to the ionic dissociation and then their attraction toward electrodes.

As mat said “In the reaction setup you'd have an anode of pure copper” Hence the reaction your talking about probably uses this specific setup, since for the people involved it is obvious.
I find it for this reason a bad question for the Olympiads… or am I just wrong about the inert electrodes?

Well I think it is a tricky question rather than a difficult one.

Which of the following is/are the product(s) of electrolysis of aqueos CuSo4?
A SO2 & O2, B Only Cu, C Only O2, Both B and C

In the question it is mentioned product(s)
and cu is an option and it is one of the product of the electrolysis so it is the answer

well the answers will be declared on 15 feb(acoording to indian time) at
www.unifiedcouncil.com/key.aspx

Yeah it is only Cu,
they ask the products of CuSO4

The answers have been declared. The right answer is (d) both b and c.

As I said earlier I do not find it good question for the olympiads; because of the absence of electrodes.