Question

During electrolysis of water the oxygen gas collects at the cathode give the correct statement
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Answer 1

During electrolysis oxygen is collected at anode and hydrogen is collected at cathode

Answer 2

a) At cathode, H

2

is evolved and at anode O

2

is evolved.

b) At cathode, H

+

ion takes two electron to convert itself into H

2

gas. 2 moles of H

+

gives 1 mole of H

2

.

2H

+

(aq)+2e

−

→H

2

(g)

At anode, OH

−

ion releases two electrons to convert into water and O

2

. 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.