Q56 · CSIR-NET Chemistry, June 2017

Paper: CSIR-NET June 2017 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Arrhenius Activation · Marks: 2 · Difficulty: Medium

Arrhenius equations for two chemical reactions are: $\mathrm{k}_{1}=\mathrm{A}_{1} \mathrm{e}^{-\mathrm{E}_{1} / \mathrm{RT}}, \mathrm{k}_{2}=\mathrm{A}_{2} \mathrm{e}^{-\mathrm{E}_{2} / \mathrm{RT}}$. If $\mathrm{E}_{1}>\mathrm{E}_{2}$ then at a given temperature T
(a)$\frac{\mathrm{k}_{1}}{\mathrm{k}_{2}}<\frac{\mathrm{A}_{1}}{\mathrm{A}_{2}}$
(b)$\frac{\mathrm{k}_{2}}{\mathrm{k}_{1}}<\frac{\mathrm{A}_{2}}{\mathrm{A}_{1}}$
(c)$\mathrm{k}_{1} \mathrm{k}_{2}>\mathrm{A}_{1} \mathrm{A}_{2}$
(d)$\mathrm{k}_{1}+\mathrm{k}_{2}>\mathrm{A}_{1}+\mathrm{A}_{2}$
Answer
Answer: A ✓ checked by 4AB · confidence high

The source book printed no answer; this one was worked out and checked — see the explanation.

Explanation
k₁/k₂ = (A₁/A₂)e^(−(E₁−E₂)/RT). With E₁ > E₂ the exponential is below 1, so k₁/k₂ < A₁/A₂ (a).

Study loop for Chemical Kinetics

1. Practise the PYQsPrevious-year questions, with answers

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