Question

What is the drawback of Collision Theory$?$

Answer 1

Hint: The collision theory helps in the study of chemical reactions, their kinetics and behaviour of gases, atoms or molecules.

Complete answer:
The collision theory is used to predict the rate of a reaction. It explains why different reactions occur at different rates and it tells different ways to change the rate of a reaction.
It states that for a chemical reaction to occur it is necessary for reacting atoms to collide with one another. There are many factors which affect the collision theory; few of them are concentration, surface area, temperature and catalysis.
A chemical reaction takes place when two reacting molecules react with sufficient energy. But for productive collision the reacting molecules must collide with sufficient kinetic energy and collide with proper orientation.
The main drawbacks of collision theory are as follow:
This theory is applicable to simple gaseous reactions only. This theory considers atoms and molecules to hard spheres without considering their structures.
There is no method for determining the steric effect for a reaction whose rate constant has not been determined experimentally.
Collision theory does not explain activation barriers. Activation barriers occur as bonds try to stretch and break in order to react and for this step some energy is required.
The theory of collision also states that the reaction frequency is proportional to total number of collisions per cc per second.
It does take into account the fast reactions where reactant molecules react despite having less energy than the activation energy.

Note:
The theory does take into account that proper molecule orientation is a requirement for a chemical reaction to take place.