WAEC Chemistry 2015 Paper

Concept:A secondary alkanol has the hydroxyl group $-\mathrm{OH}$ attached to a carbon atom that is bonded to two alkyl groups.Explanation:Check the carbon that carries the $-\mathrm{OH}$ group in each option.Ethanol is $\mathrm{CH_3CH_2OH}$. The $-\mathrm{OH}$ carbon is attached to only one alkyl group, so it is a primary alkanol.2-methylbutan-2-ol has the structure $\mathrm{(CH_3)_2C(OH)CH_2CH_3}$. The $-\mathrm{OH}$ carbon is attached to three alkyl groups, so it is a tertiary alkanol.3-methylpentan-2-ol has the structure $\mathrm{CH_3CH(OH)CH(CH_3)CH_2CH_3}$. The $-\mathrm{OH}$ carbon is attached to two alkyl groups, so it is a secondary alkanol.Propan-1-ol is $\mathrm{CH_3CH_2CH_2OH}$. The $-\mathrm{OH}$ carbon is attached to one alkyl group, so it is a primary alkanol.Therefore, the compound that is a secondary alkanol is 3-methylpentan-2-ol.Answer:Option C. 3-methylpentan-2-ol