This behavior is also used as a qualitative test for the presence of double or triple bonds in a molecule , since the reaction makes the permanganate solution colorless . It is sometimes referred to as Baeyer 's reagent . This behavior is also used as a qualitative test for the presence of double or triple bonds in a molecule , since the reaction decolourises the permanganate solution ; thus it is sometimes referred to as Baeyer 's reagent .