Question

The number of moles of nitrogen present in one litre of air containing $10$% nitrogen by volume, under standard condition, is:

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

Answer 1

The correct option is D $4.46\times {10}^{-3}moles$

The volume of nitrogen in the mixture is:

$10\%$ of the mixture $=(\frac{10}{100}\times 1)L=0.1L$

As we know that, ideal gas law states that 1 mole of an ideal gas occupies 22.4 litres by volume.

By using ideal gas law, we can calculate the moles of the nitrogen gas.

$22.4L$ of a gas $=1\text{mole}$

$\Rightarrow 0.01L$ of a gas $=\frac{1}{22.4}\times 0.1=4.46\times {10}^{-3}\text{moles}$

Hence, option $D$ is correct.