Paper: CSIR-NET June 2012 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Arrhenius Activation · Marks: 2 · Difficulty: Medium
For a reaction, the rate constant k at $27^{\circ} \mathrm{C}$ was found to be $\mathrm{k}=5.4 \times 10^{11} \mathrm{e}^{-50}$. The activation energy of the reaction is:
(a)$150 \mathrm{J} \mathrm{mol}^{-1}$
(b)$1415 \mathrm{J} \mathrm{mol}^{-1}$
(c)$115,000 \mathrm{J} \mathrm{mol}^{-1}$
(d)$1125,000 \mathrm{J} \mathrm{mol}^{-1}$
Answer
Answer: D ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
Ea/RT = 50 at 300 K ⇒ Ea = 50 × 8.314 × 300 ≈ 125,000 J mol⁻¹.