Chemistry - Mole Concept Question with Solution | TestHub

In an unknown compounds containing $\mathrm{N}$ and $\mathrm{H}$ given $\%$ of $\mathrm{H}=12.5\%$ $$\therefore \%\text{ of }N=100-12.5=87.5\%$$ $$\begin{array}{cccc}\text{ Element }& \text{ Percentage }& \text{ Atomic ratio }& \text{ Simple ratio }\\ \mathrm{H}& 12.5\%& \frac{12.5}{1}=12.5& \frac{12.5}{6.25}=2\\ \mathrm{N}& 87.5& \frac{87.5}{14}=6.25& \frac{6.25}{6.25}=1\end{array}$$ $2\times$ vapour density $=$ Mol. wt $=16\times 2=32$. Molecular formula $=n\times$ empirical formula mass $$n=\frac{32}{16}=2$$ $\therefore$ Molecular formula of the compound will be $={\left({\mathrm{NH}}_2\right)}_2$ $={\mathrm{N}}_2{\mathrm{H}}_4$