Question

Electrolysis of water is a decomposition reaction.the mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is-
1.1:1 2.2:1 3.4:1 4.1:4

Answer 1

Electrolysis of water is a decomposition reaction.

First of all what is decomposition reaction?

=> When a single reactant break down into two or more products is known as Decomposition reaction.

Decomposition reaction is of three types.

1. Thermal decomposition reaction
2. Photo decomposition reaction
3. Electric decomposition reaction

Example :

$\sf{CaCO_3\:\xrightarrow{\text{Heat}}\:CaO\:+\:CO_2}$

$\sf{2AgCl\:\xrightarrow{\text{Sunlight}}\:2Ag\:+\:Cl_2}$

$\sf{2H_2O\:\xrightarrow{\text{electricity}}\:2H_2\:+\:O_2}$

In electrolysis of water; water decomposes $\bold{\sf{(H_2O)}}$ into $\bold{\sf{H_2}}$ and $\bold{\sf{O_2}}$ gases.

Electrolysis is a process in which electrical current flows in a liquid which causes chemical changes.

In electrolysis of water; oxygen gas is liberated at cathode (negatively charged) and hydrogen gas is liberated at anode (positively charged).

[ Reaction is shown above. ]

In this 2 moles of water decomposes into 2 moles of hydrogen gas and 1 mole of oxygen gas.

Ratio of moles of Hydrogen to Oxygen is 2 : 1 and ratio of moles of Oxygen to Hydrogen is 1 : 2.

Option b) 2 : 1

Answer 2

The molecular formula of water is H2O. It contains two atoms of hydrogen and one atom of oxygen. Hence the molar ratio of hydrogen and oxygen gases liberated during electrolysis of water is 2:1.

Hope it helps...