Which of the following compounds is most likely to react with bromine water at room temperature?
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Correct answer
B. Ethene
Principle or equation
Alkenes contain a carbon-carbon double bond, which undergoes addition reactions with bromine water, decolorizing it. Alkanes, alcohols, and haloalkanes do not react with bromine water under normal conditions.
Why this answer is correct
Ethene (C2H4) is an alkene with a double bond. It reacts with bromine water (Br2 in water) via electrophilic addition to form 1,2-dibromoethane, decolorizing the orange/brown bromine water. Ethane is an alkane (saturated), ethanol is an alcohol, and chloroethane is a haloalkane; none react readily with bromine water at room temperature.
Example
Propene (C3H6) also decolorizes bromine water, forming 1,2-dibromopropane.
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