In which scenario does gas solubility typically increase in water?

Gas solubility in water is influenced primarily by temperature and pressure. As a general principle, the solubility of gases decreases with an increase in temperature. This is because higher temperatures provide gas molecules with more kinetic energy, causing them to escape from the liquid phase back into the gas phase more readily.

In contrast, when the temperature decreases, the gas molecules have less kinetic energy. This reduction allows more gas molecules to remain dissolved in the water, resulting in increased solubility. Therefore, the scenario where the temperature decreases leads to an increase in gas solubility in water is rooted in the fundamental principles of gas behavior in liquid solutions and how temperature affects kinetic energy.

Other factors such as stirring can enhance the distribution of gas in a solution but do not inherently affect the solubility of the gas in water. Changes in pressure typically have a significant positive effect on gas solubility; as pressure increases, more gas is forced into solution, consistent with Henry's law. Thus, in terms of increasing solubility, it's the decrease in temperature that is the key factor.