Question

Write any two criteria for effective collision.

Answer 1

Hint : The collision theory gives a qualitative explanation of chemical reactions and the rates at which the reactions occur. The basic principle of collision theory is that, in order for the reaction to take place, the molecules must collide.

Complete Step By Step Answer:
The collision theory is used to predict the rates of chemical reactions mainly for gases. It is based on the assumption that for a chemical reaction to occur, the reacting species should come together or collide with one another. According to the collision theory, for a chemical reaction to take place, the following criteria must be met: the molecules must collide with a sufficient amount of energy known as the activation energy so that the chemical bonds will not break. The molecules should also collide with proper orientation. A collision is said to be a successful collision or an effective collision if these two criteria are met. The rate of a chemical reaction is equal to the frequency of the effective collisions.
The following are the two criteria for effective collision:
(a) The effective fraction of collisions.
(b) The frequency of collision.

Note :
Remember that all the collisions taking place do not cause a chemical change. A collision is said to be effective in producing a chemical change only if the species brought together have a minimum value of internal energy that is equal to the activation energy of the reaction. The collision theory helps in explaining the increase in the reaction rate.