Question

The number of mole of nitrogen in 1 litre of air containing 10% nitrogen by volume under standard conditions is:

• A. 0.03 mole
• B. 2.10 mole
• C. 0.186 mole
• D. 4.46 $\times$ 10${}^{-3}$ mole

Answer 1

Answer: (D)

4.46 $\times$ 10${}^{-3}$ mole

Solution:- (D) $4.46\times {10}^{-3}$

Given that $1L$ of air contains $10\%$ nitrogen by volume.

Therefore,

Volume of nitrogen in the mixture $=\frac{10}{100}\times 1=0.1L$

Now at STP,

$1$ mole of a gas $=22.4L$

Therefoe,

No. of moles of nitrogen in $0.1L=\frac{1}{22.4}\times 0.1=4.46\times {10}^{-3}\text{mol}$

Hence the number of mole of nitrogen in $1L$ of air containing $10\%$ nitrogen by volume under standard conditions is $4.46\times {10}^{-3}\text{mol}$.