Question

The effect of temperature on the solubility of a gas in a liquid is governed by ________.

Answer 1

Henry’s law:

• Henry’s law is known as a gas law which denotes that the amount of gas that is dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid when the temperature is kept constant, which can be given as:

$\mathrm{P}\propto \mathrm{C}\left(\mathrm{or}\right)\mathrm{P}={\mathrm{k}}_{\mathrm{H}}.\mathrm{C}$

• Where $\mathrm{P}$ = partial pressure of the gas in the atmosphere above the liquid.
• $\mathrm{C}$= Concentration of the dissolved gas.
• ${\mathrm{k}}_{\mathrm{H}}$= Henry’s law constant of the gas.

Effect of temperature on solubility:

• The temperature is inversely proportional to the solubility of the gas in a liquid, hence for all gases, as the temperature increases, solubility decreases accordingly.
• The increase in kinetic energy of molecules of gas results in more motion of molecules, which breaks the intermolecular bond between liquid molecules and gas molecules and results in a decrease in solubility.
• Also, the solubility of the gas in a liquid can also be explained on the basis of Henry’s law.
• The solubility of the gas in a liquid can be related to the partial pressure of the gas in the liquid phase, which is directly proportional to Henry’s constant i.e ${\mathrm{k}}_{\mathrm{H}}$.
• Here, Henry’s constant i.e ${\mathrm{k}}_{\mathrm{H}}$ is known to be inversely related to temperature.
• Hence, with the increases in temperature the value of Henry’s constant, and it in turn tends to decrease the solubility of the gas in a liquid.

Hence, the effect of temperature on the solubility of a gas in a liquid is governed by Henry’s law.