Question

1. In the given figure a electrolysis of water is occurred. Answer the following question
(a) Name the gas collected at anode and cathode
(b) How can we test the gas collected at anode
(c) Write the balanced chemical reaction for above reaction

Answer 1

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

b) At cathode, H+ ion takes two electron to convert itself into H2 gas. 2 moles of H+ gives 1 mole of H2.

2H+(aq)+2e−→H2(g)

At anode, OH− ion releases two electrons to convert into water and O2. 2 mole OH− gives 0.5 mole O2, 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.