Question

In the electrolysis of water:
a) Name the gas collected at the cathode and anode respectively.
b) Why the volume of one gas, collected at one electrode is double than that at
the other? Name the gas.
c) How will you test the evolved gases?​

Answer 1

Answer:

a) At cathode, H2 is evolved and at anode O2 is evolved.

b) At cathode, H + ion takes two electron to convert itself into H 2gas. 2 moles of H +gives 1 mole of H 2.2H + (aq+2e − →H 2(g)At anode, OH − ion releases two electronsto convert into water and O2 . 2 mole OH −gives 0.5 mole O 2 , i.e why volume of one gas collected at one electron is double of another.

c) Acid is added to make the water conduct electricity as the distilled water is a non-conductor of electricity.