Question

$7g$ of nitrogen occupies a volume of 5 litres under certain conditions. Under the same conditions one mole of a gas, having molecular weight $56$, occupies a volume of ?

• A. $40L$
• B. $20L$
• C. $10L$
• D. $80L$

Answer 1

Answer: (B)

$20L$

Solution:- (b) 20 L

Given:-

Weight of $N_2=7g$

No. of moles of $N_2=\frac{\text{weight}}{\text{Mol. wt.}}=\frac{7}{28}=\frac{1}{4}=0.25$

Given that 7 g of nitrogen, i.e., 0.25 moles of nitrogen gas, occupies a volume of 5 litres.

$\therefore$ Volume occupied by 1 mole of a gas = $\frac{5}{0.25}=20L$