Question

The ratio of the volumes of hydrogen and oxygen obtained on electrolysis of water is ____.

• A. 1:2
• B. 2:1
• C. 4:3
• D. 1:3

Answer 1

The correct option is B 2:1

The chemical formula of water is $H_{2}O$. On electrolysis, water decomposes to produce hydrogen and oxygen gases as shown below:

$2H_{2}O\left(l\right)\to 2H_2\left(g\right)+O_2\left(g\right)$

The ratio of the volumes of hydrogen and oxygen obtained on electrolysis of water is 2:1. This is because, one molecule of water contains two hydrogen atoms and one oxygen atom in it.