A colliison between reactant molecules must occur with a certain minimum energy before it is effective in yielding Product molecules. This minimum energy is called activation energy `E_(a)` Large the value of activation energy, smaller the value of rate constant `k`. Larger is the value of activation energy, greater is the effect of temperature rise on rate constant `k`.

`E_(f) =` Activation energy of forward reaction
`E_(b) =` Activation energy of backward reaction
`Delta H = E_(f) - E_(b)`
`E_(f) =` threshold energy
If a reaction `A + B rarr C` is exothermic to the extent `30 kJ mol^(-1)` and the forward reaction has an activation energy of `249 kJ mol^(-1)` the activation energy for reverse reaction in `kJ mol^(-1)` is

Options

A. `324`
B. `279`
C. `40`
D. `100`

Answer

B

Explanation

`Delta H = E_(f)-E_(b)`
`-30 = 249-E_(b)`
`:. E_(b) = 249+30 = 279 kJ mol^(-1)`