The vapour density of a mixture containing $NO_2$ and $N_2O_4$ is 38.3 at $27^{\large\circ}C$.Calculate the mole of $NO_2$ in 100g mixture

Question

$\begin{array}{1 1}(a)\;2&(b)\;.01\\(c)\;0.437&(d)\;.234\end{array}$

Answer 1

Mol.wt.of mixture of $NO_2$ and $N_2O_4=38.3\times 2$

$\Rightarrow 76.6$

Let $a$ g of $NO_2$ present in 100g mixture.

Mole of $NO_2$+mole of $N_2O_4$=Mole of mixture

$\large\frac{a}{46}+\frac{100-a}{92}=\frac{100}{76.6}$

$a=20.10g$

$\therefore$ Mole of $NO_2$ in mixture =$\large\frac{20.10}{46}$

$\Rightarrow 0.437$

Hence (c) is the correct answer.