Question

How many litres of nitrogen gas is produced when 340 g of $N{H}_3$ (Molar mass=17 g/mol) decomposes completely at STP?

Answer 1

$N{H}_3\to \frac{1}{2}{N}_2+\frac{3}{2}{H}_2$

moles of $N{H}_3=\frac{340}{17}=20\text{mol}$

So, moles of $N_2=\frac{1}{2}\times 20=10\text{mol}$
$\therefore$ vol.of $N_2$ at STP = $10\times 22.4$ = 224 litre