We are given that:
k1 = 1.2 x 10-3 sec-1
T1 = 30 + 273 = 303 K
k2 = 2.1 x 10-3 sec-1
T2 = 40 + 273 = 313 K
Substituting these values the equation:
Log (k2 / k1)
= Ea / 2.303 R {(T2 – T1) / T1 T2}
We will get:
Log (2.1 x 10-3 sec-1/ 1.2 x 10-3 sec-1)
= Ea / 2.303 x 8.314 {(313 – 303) / 303 x 313}
Log (2.1 / 1.2) = Ea / 2.303 x 8.314 x (10 / 303 x 313)
Ea = 44126.3 J mol-1
Ea = 44.13 kJ mol-1
Hence, the energy of activation of the reaction is 44.13 kJ mol-1