Why does increasing the pressure of a gas usually increase reaction rate?

A. The increased pressure acts as a catalyst on the gas particles in the reaction.

B. The gas particles are closer, which increases the number of collisions.

C. The speed of the gas particles increases, which increases the number of collisions.

D. The surface area of the gas particles increases, which increases the number of collisions.

Answer: Option (B) is the correct answer.

Explanation:

According to collision theory, rate of a reaction generally increases when there is increase the surface area of reactants, more number of collisions between the particles etc.

Since, it is known that gas molecules have high kinetic energy. So, when pressure is applied on a gas then its particles come closer to each other. As a result, there will be increase in number of collisions between the particles.

Hence, the rate of reaction will increase will more number of collisions between the particles.

Thus, we can conclude that increasing the pressure of a gas usually increase reaction rate because the gas particles are closer, which increases the number of collisions.

I believe the answer is B.