Match List-I with List-II List-I Reagent List-II Characteristic of Co…

The correct answer is Option (1) → (A)-(IV), (B)-(III), (C)-(II), (D)-(I)

Each of these laboratory tests picks out one structural feature. Tollens’ and Fehling’s reagents are mild oxidising agents that oxidise aldehydes but not ketones; Fehling’s solution is weaker and does not oxidise aromatic aldehydes. The iodoform test needs a CH₃CO– group. The Lucas test tells the classes of alcohols apart by how fast they form an insoluble alkyl chloride.

• (A) Tollen's Reagent — This matches (IV) Aliphatic and aromatic aldehydes. Ammoniacal silver nitrate oxidises any aldehyde, aliphatic or aromatic, to the carboxylate ion and deposits a silver mirror:

      \( \displaystyle \ce{RCHO + 2[Ag(NH3)2]^+ + 3OH^- -> RCOO^- + 2Ag v + 2H2O + 4NH3} \)

• (B) Iodoform test — This matches (III) Methyl ketone. Iodine and sodium hydroxide (sodium hypoiodite) replace the three hydrogens of the methyl group next to C=O, and the yellow precipitate of iodoform separates:

      \( \displaystyle \ce{RCOCH3 + 3I2 + 4NaOH -> CHI3 v + RCOONa + 3NaI + 3H2O} \)

• (C) Lucas Reagent — This matches (II) Tertiary alcohol. Concentrated HCl with anhydrous \( \ce{ZnCl2} \) gives turbidity at once with a tertiary alcohol, because the stable tertiary carbocation forms readily; primary alcohols give no turbidity at room temperature:

      \( \displaystyle \ce{(CH3)3COH + HCl} \xrightarrow{\text{anhyd. }\ce{ZnCl2}} \ce{(CH3)3CCl + H2O} \)

• (D) Fehling's Reagent — This matches (I) Aliphatic aldehyde. The \( \ce{Cu^2+} \) complex oxidises aliphatic aldehydes and is reduced to a red-brown precipitate of \( \ce{Cu2O} \); aromatic aldehydes do not respond:

      \( \displaystyle \ce{RCHO + 2Cu^2+ + 5OH^- -> RCOO^- + Cu2O v + 3H2O} \)

Shortcut: Aromatic aldehydes are oxidised by Tollens’ reagent and not by Fehling’s, so (A) goes with (IV) and (D) with (I). Only Option (1) has both.