Question

Given below is a balanced chemical reaction for the formation of ammonia.

$N_2\left(g\right)+3H_2\left(g\right)\leftrightharpoons 2N{H}_3\left(g\right)$

Estimate the volume of hydrogen gas required to produce 44.8 litres of $N{H}_3$. (Assume the reaction takes place at STP)

• A. 22.4 L
• B. 67.2 L
• C. 44.8 L
• D. 11.2 L

Answer 1

The correct option is B 67.2 L

The given chemical equation is balanced:

$N_2\left(g\right)+3H_2\left(g\right)\leftrightharpoons 2N{H}_3\left(g\right)$

At STP, moles of gas = $\frac{\text{Volume at STP}}{\text{Molar volume}}$

Moles of $N{H}_3$ produced = $\frac{44.8}{22.4}=$
$2$ moles.
From the given chemical equation, 2 moles of $N{H}_3$ are produced from 3 moles of $H_2$
$\therefore$ Volume of hydrogen gas required = Moles $\times$ Molar volume at STP
$\Rightarrow$ Volume of hydrogen gas required = 3 $\times$ 22.4 = 67.2 litres.