Original: This behaviour 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.
Simplified: This behaviour is also used as a qualitative test for the presence of double or triple bonds in a molecule, since the reaction decolorizes the permanganate solution; thus it is sometimes referred to as Baeyer's reagent.