Given below is an expression for the rate constant of a first-order reaction occurring at a certain temperature, T (K). ln k = 14.34 − 1.25 104T The energy of activation in kcal mol-1 for the reaction is : (Given : k in s-1, R = 1.987 cal mol-1 K-1)
- 12.42
- 18.63
- 14.34
- 24.84
Answer
(4) 24.84
Solution
Arrhenius equation: ln k = ln A − EaRT
Comparing with ln k = 14.34 − 1.25 104T ⇒ EaR = 1.25 104 K
⇒ Ea = 1.25 104 1.987 cal mol-1
⇒ Ea = 24837.5 cal mol-1 ≈ 24.84 kcal mol-1
Answer: (4)