Question

For a certain reaction a large fraction of molecules has energy more than the threshold energy, still the rate of reaction is very slow. The possible reason for this could be that :

• A. the colliding molecules could be large in size
• B. the colliding molecules must not be properly oriented for effective collisions
• C. the rate of reaction could be independent of the energy
• D. one of the reactants could be in excess

Answer 1

The correct option is B the colliding molecules must not be properly oriented for effective collisions

The reaction occurs rapidly when two conditions are followed:

i) Threshold energy is less than the energy of molecules.

ii)orientation of molecules is proper for the effective collision.

so, the reaction is slow because the orientation of molecules is not proper which in turn decreases the number of effective collisions.

Option B is correct.