Why does liquid bromine reacts slowly as compared to vapours of bromine?

Explanation

In the vapour state, the molecules of bromine have more kinetic energy than in the liquid state. Therefore, collisions with the molecules of other reactants in the vapour state will be faster than in the liquid state. Moreover, in the vapour state, the surface area available for the chemical reaction is more as compared to the liqiud state. Hence, bromine in the vapour state reacts at a faster rate compared with the liquid state.