An incorrect statement about the collision theory of chemical reaction is:

1. It considers reacting molecules or atoms to be hard spheres and ignores their structural features.
2. The number of effective collisions determines the rate of reaction.
3. The collision of atoms or molecules possessing sufficient threshold energy results in product formation.
4. Molecules should collide in the proper orientation for the collision to be effective with sufficient threshold energy and proper orientation.

HINT: Effective collision depends on threshold energy and proper orientation.

Explanation:

According to the postulates of collision theory, there are following necessary conditions for any reaction to occur

(i) Molecule should collide with sufficient threshold energy.

(ii) Their orientation must be proper.

(iii) The collision must be effective.

Not only sufficient threshold energy of colliding atoms or molecules is important for effective collisonbut also the proper orientation of molecules are also required for the formation of products.