Match List-I (reaction) with List-II (product).List-IList-II(A) Aldol…

The correct answer is Option (4) → (A)-(IV), (B)-(III), (C)-(II), (D)-(I)

(A) Aldol reaction — This matches (IV) A β-hydroxy aldehyde or a β-hydroxy ketone. An aldehyde or ketone with at least one α-hydrogen, with dilute alkali, gives an aldol (or ketol):

    \( \displaystyle \ce{2CH3CHO} \xrightarrow{\text{dil. }\ce{NaOH}} \ce{CH3-CH(OH)-CH2-CHO} \)

(B) Hell-Volhard-Zelinsky reaction — This matches (III) An α-halocarboxylic acid. A carboxylic acid with an α-hydrogen is halogenated at the α-position by chlorine or bromine with a little red phosphorus (X = Cl or Br):

    \( \displaystyle \ce{R-CH2-COOH + X2} \xrightarrow{\text{red P}} \ce{R-CH(X)-COOH + HX} \)

(C) Clemmensen reduction — This matches (II) A hydrocarbon formed by reduction of the carbonyl group to a CH₂ group. Zinc amalgam and concentrated HCl reduce the \( \ce{C=O} \) group to a \( \ce{CH2} \) group:

    \( \displaystyle \ce{CH3COCH3 + 4[H]} \xrightarrow{\ce{Zn-Hg}/\text{conc. }\ce{HCl}} \ce{CH3CH2CH3 + H2O} \)

(D) Cannizzaro reaction — This matches (I) An alcohol and the salt of a carboxylic acid. An aldehyde with no α-hydrogen, heated with concentrated alkali, is partly reduced and partly oxidised:

    \( \displaystyle \ce{2HCHO + NaOH} \xrightarrow[\Delta]{\text{conc.}} \ce{CH3OH + HCOONa} \)

NCERT (2026-27 edition):
(A) 8.4 Chemical Reactions: 4. Reactions due to α-hydrogen – “(i) Aldol condensation: Aldehydes and ketones having at least one α-hydrogen undergo a reaction in the presence of dilute alkali as catalyst to form β-hydroxy aldehydes (aldol) or β-hydroxy ketones (ketol), respectively. This is known as Aldol reaction.”

(B) 8.9.4 Substitution Reactions in the Hydrocarbon Part – “1. Halogenation
Carboxylic acids having an α-hydrogen are halogenated at the α-position on treatment with chlorine or bromine in the presence of small amount of red phosphorus to give α-halocarboxylic acids. The reaction is known as Hell-Volhard-Zelinsky reaction.”

(C) 8.4 Chemical Reactions: 2. Reduction – “(ii) Reduction to hydrocarbons: The carbonyl group of aldehydes and ketones is reduced to CH₂ group on treatment with zinc-amalgam and concentrated hydrochloric acid [Clemmensen reduction] or with hydrazine followed by heating with sodium or potassium hydroxide in high boiling solvent such as ethylene glycol (Wolff-Kishner reduction).”

(D) 8.4 Chemical Reactions: 5. Other reactions – “(i) Cannizzaro reaction: Aldehydes which do not have an α-hydrogen atom, undergo self oxidation and reduction (disproportionation) reaction on heating with concentrated alkali. In this reaction, one molecule of the aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt.”