Question

describe the molecular origin of each of the three contributing factors to the rate constate.

Answer 1

Orientation of reactant molecules :
(a) In reactions involving complex molecules, the above conditions are not sufficient for the reaction to occur.
(b) Hence, apart from sufficient energy the colliding molecules must have proper orientations.
(c) If the molecules have improper orientation they do not react even if they possess the required kinetic energy.

Collision between reactant molecules :
(a) The basic requirement of collision theory is that the reacting species (atoms, ions or molecules) must come together and collide in order for the reaction to occur.
(b) Therefore, the rate of reaction must be equal to the rate of collision.
(c) However, it has been found that the rate of reaction is much lower as compared to the rate of collisions.
(d) It follows, therefore, that all the collisions between reactant molecules are not fruitful, i.e. do not result in formation of product.
(e) This implies that the collision is not the sufficient cause for the chemical reaction to occur.