Given that the normal energy of the reactant and produce are 40J and 20 J respectively and threshold energy of the uncatalysed reaction is 120 J.If the rate of uncatalysed reaction at 400 K becomes equal to the rate of catalysed reaction at 300 K, then what will be the activation energy of the catalysed forward and backward reactions respectively ?

Options

A. 80 J, 60 J
B. 60 J , 80 J
C. 80 J , 100 J`
D. 50 J, 70 J

Answer

B

Explanation

In absence of catalyst = In presence of catalyst
`E_a/T_1=E'_a/T_2 implies 80/400=E'_a/300`
`E'_a=60 Jimplies E'_b=60+20=80 J`