Question

A reaction is carried out at 400 K. If the same reaction is carried out in presence of a catalyst at the same rate, the temperature needed is 300 K. If catalyst lowers the energy of activation by $2kJmo{l}^{-1}$.

Then the activation energy of the reaction without catalyst is:

• A. 8
• B. 4
• C. 16
• D. None of these

Answer 1

The correct option is A 8

Arrhenius eqn. without catalyst
$\Rightarrow K=Aexp\left(\frac{-x}{R\left(400\right)}\right).......\left(i\right)$
Arrhenius eqn. with catalyst.
$\Rightarrow K=Aexp\left(\frac{-(x-2)}{R\left(300\right)}\right).......\left(ii\right)$
From eq. (i) and (ii)
$\frac{x}{400}=\frac{x-2}{300}$
$100x=800$
or $x=8$
The correct option is (a)