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🧪 Chemistry  ·  Chemical Kinetics  ·  NEET & JEE

In the Arrhenius equation k = A e<sup>−Ea/RT</sup>, the term A is called the:

Answer: pre-exponential factor.

  • A the rate constant
  • B pre-exponential factor
  • C the activation energy
  • D the reaction order

Correct answer: B. pre-exponential factor

Explanation: A is the pre-exponential (frequency) factor, related to the frequency and orientation of collisions.

First-Order Decay: Constant Half-Lifetime[A][A]₀[A]₀/22 × t½[A]₀/4Each successive half-life takes the SAME amount of time, regardless of starting concentration

First-order decay curve: concentration halves every t½, and that half-life is constant - a defining test for first-order kinetics.

Concept context

Study the speed of reactions and what affects it: concentration, temperature, and catalysts. Covers rate law, order of reaction, the Arrhenius equation, and reaction mechanisms step by step.

Read the full Chemical Kinetics notes →