Chemical Kinetics - Result Question 13
14. Consider the given plots for a reaction obeying Arrhenius equation $\left(0^{\circ} C < T < 300^{\circ} C\right)$ : ( $k$ and $E _a$ are rate constant and activation energy, respectively)
(2019 Main, 10 Jan I)
Choose the correct option.
(a) Both I and II are wrong
(b) Both I and II are correct
(c) I is wrong but II is right
(d) I is right but II is wrong
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Answer:
Correct Answer: 14. (b)
Solution:
- The Arrhenius equation is,
$ k=A \cdot e^{-E _a / R T} $
where, $k=$ rate constant,
$ A=\text { Arrhenius constant }, E _a=\text { activation energy, } $
and $T=$ temperature in $K$
From the equation, it is clear that $k$ decreases exponentially with $E _a$. So, the plot-I is correct.
In the plot-II, $k$ is plotted with temperature (in ${ }^{\circ} C$ but not in $K$ ). So, at $0^{\circ} $ $C, k \neq 0$ and $k$ will increase exponentially with temperature upto $300^{\circ} $ $C$. Therefore, the plot-II is also correct.
BETA
