Why does bromine react slowly as compared to bromine vapour?

Q.1 why liquid br2 reacts slowly as compared to vapours of bromine? Think about collision theory. Gas molecules possess more kinetic energy than molecules as a liquid. Gases thus have a larger frequency of collisions and, additionally, are more likely to possess sufficient energy to overcome repulsive forces, (\(i.e. E_a\)). These factors contribute to a greater likelyhood of a successful collision that results in chemical reaction.