# According to the collision theory: (A) All collisions are effective. (B) All collisions are sufficiently violent. (C) All collisions are responsible for product formation. (D) Only a fraction of collisions are effective which have enough energy to form products.

Answer: (D) Only a fraction of collisions are effective which have enough energy to form products.

The collision theory states that a chemical reaction can only occur between particles when they collide (hit each other). The collision between reactant particles is necessary but not sufficient for a reaction to take place. The collisions also have to be effective

• According to collision theory, the rate of reaction is proportional to the number of collisions per second.
• All the collisions will not result in the formation of a product.
• Only those collisions where molecules have enough activation energy and proper orientation will lead to a chemical reaction.