Question

The activation energy of a reaction is 50 kJ mol^-1 and the value of rate constant at 300 K is 2.5×10^-5 sec^-1. What is the value of the frequency factor, A?

(a) 4228.53 s^-1

(b) 3829.69 s^-1

(c) 7596.45 s^-1

(d) 6565.35 s^-1

I had been asked this question in unit test.

I want to ask this question from Chemical Kinetics in division Chemical Kinetics of Chemistry – Class 12

Answer 1

The correct choice is (c) 7596.45 s^-1

Explanation: Given,

Ea = 50 kJ mol^-1

T = 300 K

k = 1.5 × 10^-5 sec^-1

R = 8.314 J K^-1 mol^-1

log k = – Ea / (2.303 RT) + log A

OR

log A = log k + Ea / (2.303 RT)

log A = log (1.5 × 10^-5) + 50000 / (2.303 × 8.314 × 300)

log A = 3.88061

A = antilog (3.880611)

A = 7596.45 s^-1.