Final answer:
Decreasing the volume of a container increases the gas pressure and concentration due to the molecules being compressed into a confined space. This increase in pressure can shift chemical equilibria towards the side with fewer moles of gas, and in solutions, it can enhance the dissolution rate of a gas into a liquid.
Step-by-step explanation:
When the volume of a container holding gas decreases, there is a corresponding increase in pressure, which results in the gas molecules being forced closer together. This decrease in gas volume effectively increases the gas concentration within the container because there are the same number of gas molecules occupying a smaller space. As described by the principles of chemical kinetics and equilibrium, for gaseous reactions at equilibrium, an increase in pressure (caused by a decrease in volume) drives the equilibrium towards the side with fewer moles of gas. Therefore, the reaction will favor the formation of fewer gas molecules to counteract the pressure increase.
Additionally, in solutions where gases are dissolved in liquids, an increase in pressure of the gas above the liquid will lead to an increased rate of gas dissolution. When the pressure is raised, the gas molecules experience more frequent collisions with the gas-liquid boundary, thus enhancing dissolution.