Question

If the solubility of any gas in the liquid at 1 bar pressure is 0.05 mol/L. What will be it's solubility at 3 bar pressure, keeping the temperature constant?

Answer 1

Henry's law is used to calculate solubility of gases at different pressures.

By Henry's law,

P = ka × Xa.
P= pressure applied.
ka = Henry's constant.
Xa = mole fraction of gas dissolved.

As for a gas, ka is a constant,

We write,
P propotional to Xa.

Moles fraction = no of moles of gas / total moles.

As total moles is constant,
Mole fraction ,Xa propotional to number of moles.
Also, Molarity, M = no of moles / volume.

Here , we assume constant volume.
So molarity propotional to no of moles.
As number of moles already propotional to mole fraction, we can say, mole fraction propotional to Molarity.

So, we can write

P propotional to molarity.
or,
P1/P2 = M1/ M2.
1/3 = 0.05 / M2.

M2 = 0.05×3 = 0.15 M.

Hence, new solubility is 0.15 M