Question

When equal masses of methane and sulphur dioxide are taken, then the ratio of their molecules is:

• A. 1 : 1
• B. 1 : 2
• C. 2 : 1
• D. 4 : 1

Answer 1

The correct option is D 4 : 1

The molecular weights of methane and sulfur dioxide are $16$ and $64$ respectively. The ratio of their molecules is equal to the ratio of their moles. For equal masses of methane and sulphur dioxide, we know that the number of moles is inversely proportional to the molecular weight.

$\frac{MoleculesofC{H}_4}{MoleculesofS{O}_2}$ $=\frac{MolesofC{H}_4\times N_A}{MolesofS{O}_2\times N_A}$

$=\frac{Molwt.ofS{O}_2}{Molwt.ofC{H}_4}=\frac{64}{16}=4:1$