What is collision theory?

Collision theory is a concept in chemistry and physics that explains how chemical reactions occur. It states that for a reaction to take place, particles must collide with each other with sufficient energy and proper orientation. According to this theory, the rate of a chemical reaction is directly proportional to the number of collisions between reacting particles per unit time. Additionally, the theory suggests that not all collisions lead to a reaction, as the colliding particles must possess enough energy to overcome the activation energy barrier.