JAMB Chemistry 2004 Question 44

Question 44

Hydrocarbons

Which of these reagents can confirm the presence of a triple bond?

A.Bromine water
B.Acidified KMnO₄
C.Copper (I) chloride
D.Bromine gas

Show the answer and explanation

Answer: C (Copper (I) chloride)

Explanation

Bromine water and KMnO₄ are decolourised by both double and triple bonds. Ammoniacal copper(I) chloride gives a red precipitate only with alkynes having a terminal triple bond.