Question

State Henry’s law. What is the effect of temperature on the solubility of a gas in a liquid?

Answer 1

Hint: Henry’s law term is most common in physical chemistry. It is a gas law related to the solubility of a gas in terms of pressure of a gas. The relation of temperature with the solubility can also be defined on the basis of Henry’s law.

Complete step by step answer:
Now, first let us state Henry's law. It was proposed by William Henry. It states that the solubility of a gas in liquid state will be directly related to the pressure of a gas at the constant temperature.
The most common example of Henry’s law is in the case of underwater divers, or we can say the soft drinks too as they contain the dissolved carbon-dioxide.
Now, if we define it in terms of mole fraction of a gas, then we know that mole fraction of a gas is directly related to the partial pressure of a gas. Thus, Henry’s law can also be defined as the partial pressure of a gas in vapour phase is directly proportional to that of mole fraction of the gas present in the solution.
It can be written as p = K$_{H}x$ , here K$_{H}$ is Henry’s law constant.
If there is an increase in temperature, it will lead to the increase in kinetic energy, then the bonds will break, and molecules can escape from the solution. Thus, the gases will dissolve more rapidly. So, the solubility of gases will decrease in liquids.
Thus, we can conclude that as the temperature increases, solubility decreases.

Note: Don’t get confused between these terms. These are interrelated to each other. We have defined first by relating solubility to the partial pressure, then the relation of partial pressure with the mole fraction, and further the relation of temperature with the solubility of a gas.