Chemical Kinetics - Result Question 46
####46. An increase in the concentration of the reactants of a reaction leads to change in
(a) heat of reaction
[2020]
(b) threshold energy
(c) collision frequency
(d) activation energy
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Solution:
- (c) The number of collisions per second per unit volume of the reaction mixture is known as collision frequency $(Z)$. collision frequency $\propto$ no. of reacting molecules or atoms. Higher the concentration of reactant molecules higher is the probability of collision and so the collision frequency.
(c) From Arrhenius equation
$ \log \frac{k _{400}}{k _{200}}=\frac{E_a}{2.303 R}[\frac{T_2-T_1}{T_1 T_2}] $
Since, given that $E_a=0$
$\therefore \log \frac{k _{400}}{k _{200}}=0$
$\Rightarrow \frac{k _{400}}{k _{200}}=1$
So, $k _{400}=k _{200}$
So rate constant at $400, k=1.6 \times 10^{6} s^{-1}$
