A hydrocarbon `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

(i) The molecular formula suggest that it can either be a cycloalkane or alkene.
(ii) Since the hydrocarbon does not react with `Cl_(2)` in the dark, it eannot be an alkene. Therefore, it must be a cycloalkane.
(iii) The hydrocarbon reacts with `Cl_(2)` in the presence of bright sunlight to give a single monochloro compound. `C_(5)H_(9)CI` , therefore, all the ten H-atoms of the cycloalkame must be equivalent.