Question

In the Arrhenius equation for chemical kinetics, \( k = A\,e^{-\frac{E_a}{RT}} \), the parameter 'E_a' represents

• A. Frequency factor
• B. Activation energy of the reaction
• C. Universal gas constant
• D. Order of the degradation reaction

Hint:

The Arrhenius equation links how fast a reaction goes (its rate constant k) to temperature. Each symbol in the equation \( k = A\,e^{-E_a/RT} \) stands for a specific quantity.

Answer 1

The Correct Option is B

Step 1: Recall the Arrhenius equation.
The Arrhenius equation is \( k = A\,e^{-\frac{E_a}{RT}} \), where each symbol has a specific meaning.

Step 2: Identify each symbol.
\( k \) = rate constant, \( A \) = frequency factor (pre-exponential factor), \( R \) = universal gas constant, \( T \) = temperature in Kelvin.

Step 3: Focus on E_a.
E_a is the minimum energy that reacting molecules must possess for a reaction to occur. It sits in the exponent and controls how strongly temperature affects the rate.

Step 4: Eliminate the distractors.
Option 1 (Frequency factor) is actually \( A \). Option 3 (Universal gas constant) is \( R \). Option 4 (Order of reaction) is not part of the Arrhenius equation at all.

Step 5: Confirm the answer.
E_a represents the energy barrier molecules must cross for a reaction to proceed. A higher E_a means the reaction is slower at the same temperature.


Answer: Option (2) — Activation energy of the reaction