Question

The solubility of a gas in water which is exposed to the atmosphere, when the partial pressure is 700 mm is $1.4\times {10}^{-4}M$. What is the solubility of the gas at 760 mm and at same temperature?

• A. $4.1\times {10}^{-4}M$
• B. $1.52\times {10}^{-4}M$
• C. $1500M$
• D. $2.5\times {10}^{-2}M$

Answer 1

The correct option is B $1.52\times {10}^{-4}M$

From Henry's law,
$P_{gas}=K_H{X}_{gas}$
where, $X_{gas}=\text{mole fraction of gas in liquid}$
$P_{gas}\text{is the partial pressure of gas over liquid surface}$
According to Henry's Law:

So,

$\text{Solubility}\propto \text{pressure}$

$\frac{S_1}{S_2}=\frac{P_1}{P_2}\Rightarrow \frac{1.4\times {10}^{-4}}{S_2}=\frac{700}{760}$
$\Rightarrow S_2\text{(solubility at 760 mm) =}\frac{760}{700}\times 1.4\times {10}^{-4}$
$=1.52\times {10}^{-4}M$