Question

What do you mean by electrolysis of water?

Answer 1

Electrolysis of water is breaking down of water into hydrogen and oxygen by passing electricity through it.
Distilled water is a poor conductor of electricity, so water is made conducting by adding a small amount of electrolyte.

The following chemical reaction takes place when we pass electricity through water during electrolysis:

$2H_{2}O\to 2H_2+O_2$
Hydrogen gas is liberated at cathode and oxygen gas is liberated at anode.