Determine the molecular formula of an unknown hydrocarbon

CHEMISTRY · Subjective · CBSE · Chemistry · Some Basic Concepts of Chemistry · Some Basic Concepts of Chemistry

Problem

Determine the molecular formula of an unknown hydrocarbon.

15\,\mathrm{cm^3}

of a gaseous hydrocarbon was completely combusted with

95\,\mathrm{cm^3}

of oxygen in excess. After cooling to room temperature, the residual gaseous products, carbon dioxide and excess oxygen, occupied a volume of

80\,\mathrm{cm^3}

. On adding aqueous sodium hydroxide to remove

\mathrm{CO_2}

, the volume decreased to

50\,\mathrm{cm^3}

. Determine the molecular formula of the hydrocarbon.