Question

Why is there always a decreasing tendency of solubility of gases in liquid on rising temperature?

Hint:

Gases generally become less soluble in liquids as temperature increases because the increased kinetic energy of the gas molecules allows them to escape the liquid phase. Always remember that temperature increases cause gas molecules to move more energetically and tend to leave the solution.

Answer 1

The solubility of gases in liquids is generally inversely proportional to temperature, meaning that as the temperature of the liquid increases, the solubility of the gas decreases. This can be explained through the following points: 1. Increased Kinetic Energy of Gas Molecules
As the temperature increases, the kinetic energy of the gas molecules also increases. The molecules move faster, and as a result, they are more likely to overcome the intermolecular forces that hold them in the liquid. This leads to a higher tendency for the gas molecules to escape from the liquid into the gas phase. Therefore, the gas becomes less soluble in the liquid.
2. Le Chatelier's Principle
Le Chatelier's principle states that if a system at equilibrium is disturbed, the equilibrium shifts in the direction that minimizes the effect of the disturbance. For gas solubility, when temperature increases, the equilibrium shifts in such a way that more gas molecules escape the liquid phase, reducing the solubility. This is because the dissolution of gas is an exothermic process, and according to Le Chatelier's principle, increasing the temperature causes the system to favor the gas phase, thus decreasing solubility.
3. Vapor Pressure of the Gas
At higher temperatures, the vapor pressure of the gas increases. This means that the gas is more likely to escape from the liquid to the surface and enter the gas phase. Thus, with an increase in temperature, the solubility of gases decreases because more gas molecules are found in the vapor phase. 4. Entropy Considerations
As temperature increases, the disorder or entropy of the system increases. At higher temperatures, the gas molecules have more freedom of motion and are less likely to stay dissolved in the liquid. This also leads to a decrease in solubility.
In conclusion, at higher temperatures, gas molecules gain enough energy to escape from the liquid, and the solubility decreases.