1)

According to the Arrhenius equation ,

 


A) a high activation energy usually implies a fast reaction

B) rate constant increases with increases in temperature. This is due to a greater number of collisions whose energy exceeds the activation energy

C) higher the magnitude of activation energy, stronger is the temperature dependence of the rate constant.

D) the pre-exponential factor is a measure of the rate at which collisions occur, irrespective of their energy.

Answer:

Option B,C,D

Explanation:

Rate constant, $k= Ae^{-E_{a}/RT}$  where,

   $E_{a}$= activation energy and

   A= pre exponential factor

(a) If   $E_{a}$ is high, it means  lower value  of k hence, slow reaction . Thus incorrect.

(b) On increasing temperature, molecules  are raised to higher energy (greater than  $E_{a}$  ), hence number of collisions increases. Thus, correct

(c)  $\log k=\log A-\frac{E_{a}}{RT}$

$\Rightarrow$                         $\frac{d(\log k)}{dT}=\frac{E_{a}}{RT^{2}}$

Thus, when  $E_{a}$ is high, stronger is the temperature dependence of the rate constant. Thus, correct.

 (d)   Pre-exponential factor (A) is a measure of the rate at which collisions occur. Thus, correct.