And the only way you react molecules is if the reactive molecules react. So, because most of the collisions occur between solid molecules and solid molecules, that means, on average, reactions in the gas state and liquid state will be approximately the same. Now let's look at this Cage effect. Suppose we have our system where the red molecules are water solid molecules and the red and orange molecules or the molecules spoken about here, are the reactants. So notice that the red molecule is in a cage of solid molecules and before it leaves, they make many collisions with the water cage. Eventually, however, it will bounce out.