JAMB Chemistry 2022 Paper

Concept:Alkenes decolorize bromine water through an addition reaction.Explanation:Bromine water is an orange-brown reagent used to test for unsaturation.An organic compound that decolorizes bromine water must contain a carbon-carbon double bond.Among the options, only $C_2H_4$ (ethene) is an alkene.Ethene reacts with bromine water to form a colorless dibromo product.The alkanes $C_3H_8$, $C_2H_6$, and $C_4H_{10}$ are saturated and do not decolorize bromine water.Answer:D. $C_2H_4$