Question

In the electrolysis of water : (i) Name the gas collected at the cathode and anode respectively (ii) Why is the volume of one gas collected at one electrode double that at the other ? Name this gas. (iii) How will you test the evolved gases ?

Answer 1

Hydrogen at cathode oxygen at anode.

It is because in formula of water hydrogen's mass is double of oxygen.

Answer 2

(i) Oxygen at the anode and hydrogen at the cathode.
(ii) Chemical formula H2O - for every oxygen atom there are 2 hydrogen atoms. Hydrogen is double the oxygen produced.
(iii) Oxygen will relight a glowing splint. Hydrogen will make a squeaky pop sound when you put a lit splint into it.

Hope that helps!