In the Arrhenius equation, when T → ∞ then R = Ae ° = A when Ea = 0, k = A and the rate of reaction becomes independent temperature.
Role of Catalyst in a Chemical Reaction
A catalyst is a chemical substance which alters the rate of a reaction WIthout itself undergoing any permanent chemical change.
In the chemical reactions, catalyst provides an alternate pathway or reaction mechanism by reducing the activation energy between reactants and products and hence. lowering the potential energy barrier as shown.
In the presence of catalyst, activation energy decreases and hence.
where, P denotes presence of catalyst and a denotes absence of catalyst.
Theory of Reaction Rates Collision Theory
According to this theory, the reactant molecules are assumed to be hard spheres and the reaction is postulated to occur, when molecules collide with each other.
The number of collisions between the reacting molecules taking place per second per unit volume is known as collision frequency( ZAB)·