Q32 · CSIR-NET Chemistry, December 2013

Paper: CSIR-NET December 2013 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Arrhenius Activation · Marks: 2 · Difficulty: Medium

A first order gaseous reaction is $25\%$ complete in $30$ minutes at $227^{\circ}\mathrm{C}$ and in $10$ minutes at $237^{\circ}\mathrm{C}$. The activation energy of the reaction is closest to $(R=2\,\mathrm{cal\,K^{-1}\,mol^{-1}})$
(a)$27\,\mathrm{kcal\,mol^{-1}}$
(b)$110\,\mathrm{kcal\,mol^{-1}}$
(c)$55\,\mathrm{kcal\,mol^{-1}}$
(d)$5.5\,\mathrm{kcal\,mol^{-1}}$
Answer
Answer: C ✓ checked by 4AB · confidence high
Explanation
k₂/k₁ = 3; ln 3 = (Ea/R)(1/500 − 1/510) → Ea = 1.099 × 2/(3.92×10⁻⁵) ≈ 56 kcal mol⁻¹ (c).

Study loop for Chemical Kinetics

1. Practise the PYQsPrevious-year questions, with answers

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