An organic compound [A] having molecular formula gives turbidity with Lucas reagent within five…
An organic compound [A] having molecular formula $\text{C}_3\text{H}_8\text{O}$ gives turbidity with Lucas reagent within five minutes of mixing. On heating compound [A] with $\text{Cu}$ at $573\text{ K}$, compound [B] is formed. Compound [B] does not reduce Fehling’s solution but when heated with iodine and sodium hydroxide, it gives a yellow precipitate of compound [C]. Identify the compounds [A], [B] and [C]. Write the chemical reaction for the conversion of compound [B] to compound [C].
Answer
Answer
AIWritten by AI (gemini) - it can contain mistakes.
Identification:
Compound [A]: Propan-2-ol (isopropyl alcohol), $\text{CH}_3\text{CH(OH)CH}_3$
Compound [B]: Acetone (propan-2-one), $\text{CH}_3\text{COCH}_3$
Compound [C]: Iodoform (triiodomethane), $\text{CHI}_3$
Reasoning:
$C_3H_8O$ giving turbidity with Lucas reagent within 5 minutes indicates a secondary alcohol, so [A] is propan-2-ol. Catalytic dehydrogenation of [A] over $\text{Cu}$ at $573\text{ K}$ gives acetone [B], which does not reduce Fehling's solution. Acetone contains a methyl keto group, so heating with $\text{I}_2$ and $\text{NaOH}$ gives a yellow precipitate of iodoform [C].
Chemical reaction for conversion of [B] to [C]:
$\text{CH}_3\text{COCH}_3 + 3\text{I}_2 + 4\text{NaOH} \longrightarrow \text{CHI}_3\downarrow + \text{CH}_3\text{COONa} + 3\text{NaI} + 3\text{H}_2\text{O}$
From ISC 2026 Chemistry Paper 1, question 9(ii).