In some cases it is found that a large number of colliding molecules have energy more than the threshold value, yet the reaction is slow. Why?
Solution
Besides the energy barrier there is an orientation barrier.
Collisions are effective only when the molecules collide with the proper orientation (favourable alignment of the reacting parts). If the orientation is improper, even energetic collisions fail to give products — hence the reaction stays slow (the steric factor P is small).
Collisions are effective only when the molecules collide with the proper orientation (favourable alignment of the reacting parts). If the orientation is improper, even energetic collisions fail to give products — hence the reaction stays slow (the steric factor P is small).
CBSE Class 12 Board · 2004 · Delhi Compartment; also All India 2005 Compartment · Subjective