Which test distinguishes an alkene from an alkane?
Answer and explanation
Correct answer: A. Alkenes decolourise bromine water
- Step 1: The double bond in an alkene adds bromine and the orange-brown colour disappears. Answer: Alkenes decolourise bromine water. Why not the others: Alkanes decolourise bromine water: Alkanes are saturated and do not react. Both turn limewater cloudy: That is a test for carbon dioxide. Alkenes dissolve in water: Neither dissolves in water.
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