Question

grams of hydrogen are required to react with 36 grams of carbon to form methane (${\text{CH}}_4$).

• A. 12
• B. 24
• C. 72
• D. 108

Answer 1

The correct option is A 12

Gram atomic mass of carbon = 12 g
Gram atomic mass of hydrogen = 1 g
The chemical formula of methane is ${\text{CH}}_4$.
In other words, one mole carbon and four moles of hydrogen are present in one mole of ${\text{CH}}_4$. So, the carbon to hydrogen mass ratio in methane is 12:4 i.e. 3:1.

3 grams of carbon require 1 gram of hydrogen gas to form methane.

So, 36 grams of carbon require $\frac{36}{3}\times 1=12\text{grams}$ of hydrogen gas.