Question

How oxygen is formed during electrolysis of water ?

Answer 1

Dear student

Electrolysis of water means passing electric current through water to decompose it into hydrogen gas and oxygen gas. The reaction that takes place during the process can be shown as:-

2H₂O → 2H₂ +O₂

Graphite rod acts as cathode and anode in water electrolysis.

Hydrogen and oxygen gases are collected at cathode and anode respectively.

At cathode:-

Reduction

2 H⁺ (aq) +2e^- → H₂

At anode:-

Oxidation

OH^- (aq) → OH + e^-

4 OH → 2H₂O + O₂

As cathode is negatively charged so H⁺ (being positive) attract towards cathode and anode is positively charged so OH^- (being negatively charged) attract towards anode. Therefore, hydrogen is liberated at cathode and oxygen is liberated at anode respectively.

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