For a first order chemical reaction,

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) . The Arrhenius equation for the rate constant $k$ is $k = A e^{-E_a / RT}$,where $A$ is the pre-exponential factor.Since the term $e^{-E_a / RT}$

Vedclass · Accepted Answer

the dimension of Arrhenius pre-exponential factor is reciprocal of time.

Vedclass · Answer

(C) . The Arrhenius equation for the rate constant $k$ is $k = A e^{-E_a / RT}$,where $A$ is the pre-exponential factor.Since the term $e^{-E_a / RT}$ is dimensionless,the dimension of $A$ is equal to the dimension of $k$.For a first-order reaction,the dimension of $k$ is $	ext{time}^{-1}$.Therefore,the dimension of $A$ is also $	ext{time}^{-1}$,which is the reciprocal of time.Regarding other options:For a first-order reaction,the rate of reaction is directly proportional to the reactant concentration.The half-life $t_{1/2} = \frac{0.693}{k}$,which is $69.3 \%$ of $\frac{1}{k}$.The concentration of the reactant changes with time according to the equation $[A]_t = [A]_0 e^{-kt}$,which represents an exponential decay,not a linear one.

Similar Questions

For a first-order reaction,if the rate constant is $k_1$ at temperature $T_1$ and $k_2$ at temperature $T_2$,which of the following relations is correct? ($E_a$ = activation energy)

For a reaction,$A \rightarrow B$,the average energies of $A$ and $B$ are $30 \ kcal/mol$ and $60 \ kcal/mol$ respectively. The energy of activation for the backward reaction is $93 \ kcal/mol$. The energy of activation for the forward reaction is:

According to the Arrhenius equation, which of the following statements is correct?

The rate of a chemical reaction doubles for every $10\,^{\circ}C$ rise in temperature. If the temperature is increased to $50\,^{\circ}C$ from $0\,^{\circ}C$,by how many times will the rate of reaction increase?

Why does the rate of a reaction increase with a rise in temperature?

Vedclass Test Series

Exam Paper Generator

Online Exam Module