In this example question, it says for chemical reaction to occur, all the following must happen except. All right. So here a large number of collisions must occur. Chemical bonds and reactants must break. Reactant molecules must collide with correct orientation, Reactant molecules must collide with enough energy or none of the above.

All right, so let's make sure we take out the ones that we know have to happen. So here reactive molecules must collide with correct orientation. This is one of the foundations of collision theory we talked about. They have to basically connect in the right spots. So here this has to happen. What else must happen? Reactive molecules must collide with sufficient energy. Enough energy.

Now here we have AB and E. So for B we say chemical bonds in reactants must break. Well, the whole point of these chemical reactions is to change reactants into products, and reactants can only change into products if their bonds break. So B has to happen. The answer here is A. Yes, collisions need to occur for them to stick together, but it's not necessary that it has to be a large enough number of collisions.

Some reactions can happen with just a few collisions because they're highly favorable. So here A would be the best answer. We need collisions. We don't always necessarily need a large number of collisions. Again, some reactions only need a few and they automatically stick together, right? So here the final answer would be option A.