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🧪 Chemistry  ·  Chemical Kinetics  ·  NEET & JEE

The pre-exponential factor A in the Arrhenius equation represents:

Answer: Collision frequency and steric factor.

  • A Activation energy under typical conditions
  • B Collision frequency and steric factor
  • C Temperature coefficient according to standard textbooks
  • D Rate at 0 K in general practice

Correct answer: B. Collision frequency and steric factor

Explanation: A = collision frequency × orientation probability (steric factor). It accounts for how often molecules collide with the right orientation.

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 →