Why does increasing pressure of reacting gases lead to a higher reaction rate according to collision theory?

Increasing the pressure of reacting gases leads to an increased reaction rate primarily because it increases the frequency of collisions between the gas molecules. According to collision theory, chemical reactions occur when reactant particles collide with sufficient energy and in the correct orientation. When the pressure of a gas is increased, the gas molecules are compressed into a smaller volume, which results in more molecules being present in a given space. This high concentration of molecules means that they are more likely to collide with one another.

As these collisions increase in frequency, the likelihood of effective collisions—those that result in a chemical reaction—also rises, thereby accelerating the rate of the reaction. Therefore, the correct choice highlights this fundamental principle of collision theory, emphasizing the impact of increased pressure on molecular interactions and reaction kinetics.