How do unsaturated compounds react with bromine solution?

Unsaturated compounds, which contain double or triple bonds in their molecular structure, readily react with bromine solution. This reaction involves the addition of bromine across the double or triple bond, leading to a saturation of the molecule. This process is characterized by the decolorization of the bromine solution, which transitions from its distinctive brownish-orange color to colorless as the bromine is consumed during the reaction.

The speed of this decolorization is what distinguishes the reactivity of unsaturated compounds, indicating that they are more reactive due to the presence of the reactive pi bonds. This is a valuable qualitative test for the presence of unsaturation in organic compounds, as saturated compounds, which do not have these double or triple bonds, would not react with bromine in this way and thus would leave the solution unchanged.