Question

The solubility of $N_2\left(g\right)$ in water exposed to the atmosphere, when the partial pressure is $593mm$ is $5.3\times {10}^{-4}M$. Its solubility at $760mm$ and at the same temperature is:

• A. $4.1\times {10}^{-4}M$
• B. $6.8\times {10}^{-4}M$
• C. $1500M$
• D. $2400M$

Answer 1

The correct option is B $6.8\times {10}^{-4}M$

From Henry's law,

$P_{gas}=K_H{X}_{gas}$

where, $X_{gas}$= mole fraction of gas in liquid.

$P_{gas}$= partial pressure of gas over liquid surface.

Solubility $\propto$ Pressure

So, $\frac{S_1}{S_2}=\frac{P_1}{P_2}\Rightarrow \frac{5.3\times {10}^{-4}}{S_2}=\frac{593}{760}$

$\Rightarrow S_2$ (Solubility at $760mm$)=$\frac{760}{593}\times 5.3\times {10}^{-4}$

$=6.79\times {10}^{-4}M\approx 6.8\times {10}^{-4}M$.