Propene plus bromine water yields which product?

• A. Propene
• B. Dibromopropane
• C. Propyl bromide
• D. Dipropyl bromide

Answer: (B)

Propene has a carbon–carbon double bond that can react with bromine through electrophilic addition. When bromine water (Br2) meets an alkene, the double bond reacts with Br2 and each of the adjacent carbons bonds to a bromine atom, breaking the Br–Br bond in the process. The result is a vicinal dibromide, specifically 1,2-dibromopropane, where bromine atoms attach to the two carbon atoms that were involved in the double bond. This reaction also causes the bromine color to disappear from the solution, showing that the unsaturation has been consumed.

So the product is dibromopropane. The other options don’t fit this reaction pattern: a simple propene molecule is the starting material, propyl bromide would come from substitution under different conditions, and dipropyl bromide would require coupling two propyl groups, not addition to a double bond.