Question

It’s way easier for two molecules to react than three because getting three to collide perfectly at the same time with the right energy is really unlikely. Two molecules have a much better chance of hitting just right.
rephrase like a 8th grader

Answer 1

It’s much easier for two molecules to react with each other than for three because it’s really rare for three molecules to bump into each other in just the right way with enough energy at the same time. When there are only two molecules, they have a much better chance of colliding perfectly.