Question

Electrolysis of water is a decomposition reaction. The mass ratio (M_H : M_O) of hydrogen and oxygen gases liberated at the electrodes during electrolysis of water is ______.

Options

• 8 : 1

• 2 : 1

• 1 : 2

• 1 : 8

Answer 1

Electrolysis of water is a decomposition reaction. The mass ratio (M_H : M_O) of hydrogen and oxygen gases liberated at the electrodes during electrolysis of water is 1 : 8.

Explanation:

Electrolysis of water follows the reaction:

\[\ce{2H2O -> 2H2 + O2}\]

• Hydrogen (H₂) is produced in a 2 : 1 volume ratio with oxygen (O₂)
• Mass of hydrogen produced = 2 × 1 = 2 g
• Mass of oxygen produced = 1 × 16 = 16 g
• Mass ratio of hydrogen to oxygen = 2 : 16 = 1 : 8