Match List-I with List-II List-I (Name of Reaction) List-II (Reagents…

The correct answer is Option (3) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

All four are named reactions for making aldehydes and ketones, and each is known by its reagent. Three of them give aldehydes by partial reduction or partial oxidation (Stephen from a nitrile, Rosenmund from an acyl chloride, Etard from a methylbenzene); the fourth gives an aromatic ketone by electrophilic substitution.

• (A) Stephen reaction — This matches (III) \(SnCl_2, HCl\). A nitrile is reduced by stannous chloride and HCl to an imine, which is hydrolysed to an aldehyde:

      \( \displaystyle \ce{RCN} \xrightarrow{\ce{SnCl2 + HCl}} \ce{RCH=NH} \xrightarrow{\ce{H3O^+}} \ce{RCHO} \)

• (B) Rosenmund reduction — This matches (IV) \(H_2/Pd-BaSO_4\). An acyl chloride is hydrogenated over palladium on barium sulphate; the catalyst is poisoned so that the aldehyde is not reduced further to an alcohol:

      \( \displaystyle \ce{C6H5COCl + H2} \xrightarrow{\ce{Pd-BaSO4}} \ce{C6H5CHO + HCl} \)

• (C) Etard reaction — This matches (I) \(CrO_2Cl_2/CS_2\). Chromyl chloride oxidises the methyl group of toluene to a chromium complex, which on hydrolysis gives benzaldehyde:

      \( \displaystyle \ce{C6H5CH3} \xrightarrow[\text{(ii) }\ce{H3O^+}]{\text{(i) }\ce{CrO2Cl2}/\ce{CS2}} \ce{C6H5CHO} \)

• (D) Friedel-Crafts acylation — This matches (II) Acyl chloride and anhyd. \(AlCl_3\). The Lewis acid generates the acylium ion, \( \ce{RCO+} \), which substitutes the benzene ring to give a ketone:

      \( \displaystyle \ce{C6H6 + CH3COCl} \xrightarrow{\text{anhyd. }\ce{AlCl3}} \ce{C6H5COCH3 + HCl} \)

Shortcut: (A)-(III) and (B)-(IV) appear together in Options (1) and (3); (C)-(I) then leaves only Option (3).