For `A+B rarr C+D, DeltaH=-20 kJ mol^(-1)`, the activation energy of the forward reaction is `85 kJ mol^(-1)`. The activation energy for backward reaction is …… `kJ mol^(-1)`.

Options

A. 65
B. 105
C. 85
D. 40

Explanation

For a reaction
`DeltaH = E_(a(f))-E_(a(b))`
`:. E_(a(b))=E_(a(f))-DeltaH`
`=85 -(-20)`
`= 105 kJ mol^(-1)`