Question

If a mixture of $3$ moles of $H_2$ and one mole of $N_2$ is completely converted into $N{H}_3$. What would be the ratio of the initial and final volume at same temperature and pressure?

Answer 1

$N_2+3H_2\rightleftharpoons 2N{H}_3$
$1$ $3$ $0$ ---- Initial moles
$0$ $0$ $2$ ( $\because$ complete conversion) ---- Final moles

Ratio of initial and final volumes $=\frac{initialmoles}{finalmoles}$

$(\because V\propto n$ if $P$ and $T$ are constant) $=\frac{4}{2}=2$.