Question

Rate of which reaction increases with temperature:
(A) Any reaction
(B) Exothermic reaction
(C) Endothermic reaction
(D) None of these

Answer 1

Hint: To answer this question we must have a clear idea of chemical kinetics and activation energy. We must remember that the kinetic energy of particles always increases with increase in temperature.

Complete step by step solution:
We should remember that increasing the temperature always increases reaction rates because of the disproportionately large increase in the number of high energy collisions between molecules.
Temperature is actually a measure of the average kinetic energy of molecules in motion.
Molecules in motion tend to stay in motion until an external force is applied on them, and when different reactant molecules are mixed together, they have much more chances of collision with each other.
If the temperature is raised, the kinetic energies of all reactants are increased so that there are more collisions per second, and a greater fraction of these will lead to chemical reaction. The rate, therefore, generally increases with increasing temperature.
We can see from Arrhenius' equation that the rate of all reactions increases with increase in temperature irrespective of the fact whether they are exothermic or endothermic.
\[\ln \,k = \dfrac{{ - Ea}}{{RT}} + \ln \,A\]

Hence, the correct answer is Option (A) any reaction.

Additional information:
When temperature increases, the amount of atomic or molecular collisions between these molecules increases. But this change in reaction rate with temperature is not only a function of the temperature; instead, temperature increases actually affect the rate constants (written k) of reactions in a predictable way.

Note: It is observed as a general rule that the rate of homogeneous reaction almost doubles with every ten degree rise in temperature. This ratio of rate constant is called temperature coefficient of a reaction.