Question

In a bimolecular reaction, the steric factor $P$ was experimentally determined to be $4.5$. The correct option(s) among the following is (are):

• A. Experimentally determined value of frequency factor is higher than that predicted by Arrhenius equation.
• B. The value of frequency factor predicted by Arrhenius equation is higher than that determined experimentally.
• C. The activation energy of the reaction is unaffected by the value of the steric factor.
• D. Since $P=4.5$, the reaction will not proceed unless an effective catalyst is used.

Answer 1

Answer: (A), (C)

The correct options are
A Experimentally determined value of frequency factor is higher than that predicted by Arrhenius equation.
C The activation energy of the reaction is unaffected by the value of the steric factor.

$\rho =4.5$

$\therefore \rho >1$

We know, $\frac{K_{exp}}{K_{collision}}=\rho$

$K_{exp}=\rho A{e}^{\frac{-E_a}{RT}}$

$A_{exp}=\rho A$

$\therefore A_{exp}>A$

$\therefore$ experimentally determine value of frequency factor is higher than that predicted by Arrhenius equation.

$\therefore$ option $A$ is correct and $B$ is incorrect.

$K_{exp}=\rho A{e}^{\frac{-E_a}{RT}}$

Since in this equation $E_a$ is not changed, option $C$ is correct.

Since $K_{exp}>K$, there is no need of an effective catalyst to reduce activation energy so that $K_{exp}$ increases.

$\therefore$ option $D$ is not correct.