Question

A hydrocarbon ${\mathrm{C}}_5{\mathrm{H}}_{10}$does not react with chlorine in dark but gives a single monochloro compound ${\mathrm{C}}_5{\mathrm{H}}_9\mathrm{Cl}$ in bright sunlight. Identify the hydrocarbon.

Answer 1

Identification of the hydrocarbon :

1. The molecular formula of hydrocarbons is ${\mathrm{C}}_5{\mathrm{H}}_{10}$, which satisfies the general formula ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}$
2. This suggests that the hydrocarbon can either be alkene or cycloalkane.
3. Since the hydrocarbon does not react with chlorine in the dark, it cannot be alkene. Therefore, the hydrocarbon is a cycloalkane.
4. Cycloalkane gives a single monochloro compound ${\mathrm{C}}_5{\mathrm{H}}_9\mathrm{Cl}$ in bright sunlight.

Hence the hydrocarbon identified is ${\mathrm{C}}_5{\mathrm{H}}_9\mathrm{Cl}$ cyclochloropentane.