Question

The vapour density of air is:

• A. 14.4
• B. 14
• C. 22
• D. None of the above

Answer 1

Answer: (A)

$\begin{array}{c}\text{Consider Air contains}80\%N_2\text{and}20/O_2\\ \text{Vapour Density}=\frac{\text{Molar Mass}}{2}\\ \text{Since Aiv is a mixture, Average Molar}\\ \text{Mass is taken}\\ \text{Aug Molar Mass}=\frac{8\times 28+2\times 32}{10}=28\\ \text{(Aug Molar Mass}=\frac{M_1\times n_1+M_2{n}_2}{n_1+n_2})\\ \text{Hence Vapour density will be}14.4\end{array}$