Question

The volume of 170 g of ${\text{NH}}_3$ at STP is _______.

• A. 2.24 L
• B. 224 L
• C. 7.58 L
• D. 0.45 L

Answer 1

The correct option is B 224 L

Given mass of ammonia (${\text{NH}}_3)$ = 170 g
Molar volume of ${\text{NH}}_3$ at STP (in litres) = 22.4 L
Gram molecular mass of ${\text{NH}}_3$ = 17 g

Number of moles = $\frac{\text{Given mass}}{\text{Gram molecular mass}}$
$\therefore$ Number of moles of ${\text{NH}}_3$ = $\frac{170}{17}$ = 10 mol

In case of gases at STP,
1 mole of ${\text{NH}}_3$ occupies 22.4 L
$\therefore$ Volume occupied by 10 moles of ${\text{NH}}_3$ at STP = 22.4 $\times$ 10 = 224 L