Organic Compounds belonging to different organic families have distinguished test results with various reagents. For example, alkene reacts with bromine water and undergoes an additional reaction. This can be used as a test for unsaturation. To distinguish between propenal, propanal and propanone, following reagents can be used: Bromine Water: Only propenal will react with bromine water due to presence of a double bond, and the solution turns colourless. Propanal and Propanone do not react with it. Tollen’s Reagent: Tollen’s reagent is an ammoniacal silver (I) nitrate solution, and has oxidising properties. Only propanal reacts with it, and oxidise to produce a silver mirror. Propanone does not react with it.