EVERYDAY SCIENCE

Detailed explanation-1: -Ethene, butyne, and hexyne can decolourize bromine water. The bromine loses its original red-brown color to give a colorless liquid.

Detailed explanation-2: -Bromine is a dark red-brown liquid, but alkenes and dibromoalkanes are colorless. Thus, a dilute solution of bromine in an inert colorless solvent, such as dichloromethane, is rapidly decolorized when it is added to an alkene.

Detailed explanation-3: -Assertion :Unsaturated hydrocarbons decolorize the red coloured bromine water. Reason: Unsaturated hydrocarbon undergoes substitution reaction with bromine water.

Detailed explanation-4: -Alkenes are a class of unsaturated hydrocarbons which contain at least one carbon-to-carbon double bond. When bromine water is added to a liquid sample of an alkene, the bromine water is decolorized.