Question

In which of the following sets, reactant and reagent are correctly matched to get corresponding carboxylic acid? \[ \begin{array}{ll} \textbf{I.} & \mathrm{CH_3CH_2CH_2OH} \;\xrightarrow{\mathrm{CrO_3,\ H_2SO_4}}\; ? \\[2mm] \textbf{II.} & \mathrm{CH_3CH_2CH_2Br} \;\xrightarrow{\mathrm{CO,\ H_3O^+}}\; ? \\[2mm] \textbf{III.} & \mathrm{CH_3CHO} \;\xrightarrow{\mathrm{KMnO_4/OH^-,\ H_3O^+}}\; ? \end{array} \] The correct answer is

• A. I only
• B. I, II only
• C. I, III only
• D. II only \bigskip

Hint:

Primary alcohols and aldehydes can be oxidised to carboxylic acids using strong oxidising agents such as: \[ \mathrm{KMnO_4,\ K_2Cr_2O_7,\ CrO_3/H_2SO_4} \]

Answer 1

The Correct Option is C

Step 1: Analyse Statement I. Primary alcohols are oxidised by Jones reagent \((\mathrm{CrO_3/H_2SO_4})\) to the corresponding carboxylic acids. \[ \mathrm{CH_3CH_2CH_2OH} \;\xrightarrow{\mathrm{CrO_3/H_2SO_4}}\; \mathrm{CH_3CH_2COOH} \] Hence, Statement I is correct.

Step 2: Analyse Statement II. Alkyl bromides are not directly converted into carboxylic acids using only CO and \(\mathrm{H_3O^+}\). Carbonylation requires specific catalysts and conditions. Hence, Statement II is incorrect.

Step 3: Analyse Statement III. Aldehydes are readily oxidised by alkaline potassium permanganate to carboxylic acids. \[ \mathrm{CH_3CHO} \xrightarrow{\mathrm{KMnO_4/OH^-,\ H_3O^+}} \mathrm{CH_3COOH} \] Hence, Statement III is correct.

Step 4: Final conclusion. Therefore, the correct statements are \[ \boxed{\text{I and III only}.} \] Hence, the correct option is \(\boxed{(C)}\).