A hydorcarbon `C_(5)H_(10)` does not react with chlorine in dark but gives a single monochloro compound `C_(5)H_(9)Cl` in bright sunlight. Identify the hydrocarbon.

Explanation

Molecular formula of the hydrocarbon is `C_(5)H_(10)` (i.e., `C_(n)H_(2n))` type). So it is either an alkene or a cycloalkane. But the compound does not react with `Cl_(2)` in the dark. So it is not an alkene but must be a cycloalkane. Since it reacts with `Cl_(2)` in bright sunlight to give a single monochloro derivative `(C_(5)H_(9)Cl)`, therefore all the ten H-atoms of the hydrocarbon must be equivalent. Thus, the given hydrocarbon is cyclopentane.
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