NEETChemistryChemical Kinetics
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For a given rise in temperature, a reaction with a higher activation energy shows a greater percentage increase in its rate constant compared to a reaction with a lower activation energy. Reason (R): The rate constant of a chemical reaction is directly proportional to its activation energy. In the
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
C. (A) is true but (R) is false
Step-by-step solution
From the Arrhenius equation, the relationship between rate constants at two temperatures is: ( k₂ k₁ ) = E_a 2.303 R ( T₂ - T₁ T₁ T₂ ) For a constant temperature interval ( T₂ - T₁ ), the value of (k₂/k₁) is directly proportional to the activation energy ( E_a ). Therefore, a reaction with a higher E_a will have a larger ratio of k₂/k₁ , meaning it exhibits a greater percentage increase in its rate constant. Thus, the Assertion (A) is true. According to the Arrhenius equation, k = A e^ -E_a/RT . This indicates that