The following statements predict the temperature dependence on the rate of reaction:

(A) Increase in temperature increases the rate of reaction.
(B) Increase in temperature decreases the rate of reaction.
(C) Increase in temperature by 10℃ doubles the reaction rate.
(D) An increase in temperature by 10℃ triples the rate of reaction.

Choose the correct answer from the options given below:

(A) and (C) only

The correct answer is Option (1) → (A) and (C) only

Temperature affects reaction rate through the Arrhenius equation:

$k = A e^{(-Ea/RT)}$

Increase in temperature increases the fraction of molecules having energy activation energy.

Statement A

When temperature increases, the kinetic energy of reactant molecules increases. This leads to:

• Higher collision frequency

• Greater number of molecules with sufficient activation energy

Hence, more effective collisions occur, increasing reaction rate.

Statement B

Increase in temperature does not decrease rate under normal reaction conditions. Only in rare cases involving equilibrium shift or catalyst deactivation can rate reduce, which is not the general kinetic behavior.

Statement C

According to the Van't Hoff rule:

For many reactions, rate increases by about 2 times for every 10°C rise.

This happens because exponential dependence of rate constant on temperature increases the number of activated molecules significantly. Hence, this is considered approximately correct.

Statement D

Tripling of rate is not a general rule. It may occur in reactions with very high activation energy but cannot be universally applied. Therefore, this statement is not generally valid.