Question

Which of the following statements are in accordance with the Arrhenius equation?

• A. Rate of a reaction increases with decrease in activation energy.
• B. Rate constant decreases exponentially with increase in temperature.
• C. Rate of a reaction increases with increase in temperature.
• D. Rate of reaction decreases with decrease in activation energy.

Answer 1

Answer: (A), (C)

Rate of a reaction increases with increase in temperature.

Explaining the Arrhenius equation

Arrhenius equation: $k=A{e}^{\frac{-E_a}{RT}}$

Where, $k=$ rate constant

$A=$ pre-exponential factor

$E_a=$ activation energy

$R=$gas constant

$T=$ temperature

Effect of temperature and activation energy on rate of reaction

Using Arrhenius equation:

$k=A{e}^{\frac{-E_a}{RT}}$

When $T$ increases $\to Ea/RT$ decreases

$\to \frac{-E_a}{RT}$ increases $\to k=A{e}^{\frac{-E_a}{RT}}$

increases $\to k$ increases $\to$ rate of reaction increases.

When $E_a$ decreases $\to \frac{E_a}{RT}$ decreases $\to \frac{-E_a}{RT}$ increases $\to e^{\frac{-E_a}{RT}}$ increases $\to k$ increases $\to$ rate of reaction increases.

Hence, options $\left(A\right)$ and $\left(B\right)$ are the correct answers.