Question

describe an activity to show how electrolysis of water is carried out​

Answer 1

Water is decomposed into hydrogen and oxygen gases using electricity.  A Hoffman electrolysis apparatus collects the two gases separately and shows the 2 to 1 ratio nicely.  If a pH indicator is used the anode becomes yellow and cathode becomes blue.  Hydrogen gas can be burned to produce a small pop sound and the oxygen can be used to re-ignite a glowing wooden splint.