Question

At a partial pressure of $600mmHg$ and $298K$, the solubility of a gas in water which is exposed to the atmosphere is $1\times {10}^{-4}M$. Calculate the solubility of the gas at $700mmHg$ and at same temperature?

• A. $1.16\times {10}^{-4}M$
• B. $2.55\times {10}^{-3}M$
• C. $1\times {10}^{-2}M$
• D. $0.5\times {10}^{-3}M$

Answer 1

The correct option is A $1.16\times {10}^{-4}M$

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,

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

$\frac{S_1}{S_2}=\frac{P_1}{P_2}\Rightarrow \frac{1\times {10}^{-4}}{S_2}=\frac{600}{700}$
$\Rightarrow S_2\text{(solubility at 700 mm) =}\frac{700}{600}\times 1.16\times {10}^{-4}$
$S_2=1.16\times {10}^{-4}M$