Question

According to the collision theory:
A. Collisions are sufficiently violent
B. All collisions are responsible for reaction
C. All collisions are effective
D. Only sufficiently energetic molecules have enough energy to react

Answer 1

Hint: The collision theory describes the gas-phase chemical reactions that occur when molecules collide with sufficient kinetic energy. Thus, the rate at which a chemical reaction occurs is equal to the frequency of effective collisions.

Complete step-by-step answer:
According to the collision theory, the reactants must collide with sufficient energy so that chemical bonds between the atoms can easily break. This sufficient energy is known as the activation energy.
The molecules must collide with a proper orientation for a chemical reaction to occur. As the temperature increases, molecules tend to move faster and thus collide more vigorously. This increases the chance of bond breakage upon collision.
We know that the rate of chemical reaction is directly proportional to the number of collisions per second. This is because proper collision leads to a chemical reaction. The reaction rate increases when more reactant molecules collide with one another.Therefore, according to collision theory, only sufficient energetic molecules have enough energy to react.
Not all collisions are effective because of orientational requirements. Not all collisions have sufficient activation energy and so all are not sufficiently violent. All collisions are not responsible reactions because not all collisions have enough energy for a reaction to take place and not all collisions have proper orientation for a reaction to occur.

Hence, the correct option is (D).

Note: It explains why most reaction rates increase as concentration increases. When concentration of any reacting substance increases, the chances for collisions between molecules are increased due to more molecules per unit of volume resulting in faster reaction rate.