JEE Main · 2023 · 25 Jan 2023 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

The ceric ammonium nitrate test gives a red colouration only with alcohols, while a positive iodoform test needs a $\mathrm{C}{\mathrm{H}}_3\mathrm{CH}(\mathrm{OH})-$ or $\mathrm{C}{\mathrm{H}}_3\mathrm{CO}-$ unit. A compound answering both must therefore be an alcohol that also carries the $\mathrm{C}{\mathrm{H}}_3\mathrm{CH}(\mathrm{OH})-$ grouping. Acetophenone and acetaldehyde give iodoform but, being a ketone and an aldehyde, fail the alcohol test; diethyl ether answers neither; 2-phenylethanol and 2-cyclohexylpropan-2-ol respond to the ceric test but lack the $\mathrm{C}{\mathrm{H}}_3\mathrm{CH}(\mathrm{OH})-$ unit and so give no iodoform. Butan-2-ol, 1-phenylpropan-2-ol and 1-cyclohexylpropan-2-ol each hold a secondary $\mathrm{C}{\mathrm{H}}_3\mathrm{CH}(\mathrm{OH})-$ group and each responds to both tests. The number of compounds satisfying both conditions is three.