The correct expression of the rate of the reaction according to the collision theory is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → $PZ_{AB} e^{-Ea/RT}$
Collision theory states that for a reaction to occur, molecules must collide with:
- Sufficient energy (≥ activation energy)
- Proper orientation
So rate depends on number of collisions, orientation factor, and energy factor.
Option 2: $PZ_{AB} e^{-E_a/RT}$
Complete expression of collision theory rate constant:
- $Z_{AB}$ = collision frequency
- $P$ = steric factor (proper orientation)
- $e^{-E_a/RT}$ = fraction of energetic molecules
This matches Arrhenius form $k = Ae^{-E_a/RT}$, where $A = PZ$.