Question

Assertion:If the activation energy of the reaction is zero, temperature will have no effect on the rate constant.
Reason:Lower the activation energy faster is the reaction.
A) Both Assertion and Reason are correct and reason is the correct explanation for the Assertion.
B) Both Assertion and Reason are correct but Reason is not the correct explanation for the Assertion.
C) Assertion is correct but Reason is incorrect
D) Assertion is incorrect but Reason is correct.

Answer 1

Hint: In the reaction reacting molecules are combined to form the product and energy is required for this conversion. This minimum amount of energy required for conversion of the reactants to products is known as the activation energy.
It is generally represented as \[{{\text{E}}_{\text{a}}}\].Activation energy is inversely proportional to the rate of the reaction. The rate of reaction indicates the speed of the reaction. Higher is the activation energy slower is the reaction rate and vice versa.

Complete answer:
Here, we have to use the Arrhenius equation.
\[{\text{k = A}} \times {{\text{e}}^{{\text{ - }}{{\text{E}}_{\text{a}}}{\text{/RT}}}}\]
In the Assertion, it is given that the activation energy is zero. Therefore, substitute \[{{\text{E}}_{\text{a}}} = 0\] in the above equation.
\[{\text{k = A}} \times {{\text{e}}^{{\text{ - 0/RT}}}}\]
\[{\text{k = A}} \times {{\text{e}}^{\text{0}}}\]
\[{\text{k = A}}\]
Here, we can see that the rate constant is independent of the temperature.
Therefore, the Assertion If the activation energy of the reaction is zero, the temperature will not affect the rate constant is correct.
As the activation energy is inversely proportional to the rate of the reaction the reason ‘Lower the activation energy faster is the reaction’ is correct.
But the given reason is not the correct explanation for the given Assertion.
Here, option (A) Both Assertion and Reason are correct and reason is the correct explanation for the Assertion is incorrect.
Now, Option (C) Assertion is correct but Reason is incorrect.
Here, option (D) Assertion is incorrect but Reason is correct is also incorrect
Here, option (B) Both Assertion and Reason are correct but Reason is not the correct explanation for the Assertion is the correct answer to the given question.

Note:The effect of the temperature on the rate of the reaction is explained using the Arrhenius equation.The temperature is directly proportional to the rate of the reaction.As the temperature increases, the kinetic energy of the molecules increases leads to an increase in the effective collision between the reactant molecules, and hence, larger numbers of the molecules are converted into the products.In this way, the temperature decides the rate of the reaction.