Match List - I with List - II.

List - I (Reactions)	List - II (Reagents)
(A) CH₃(CH₂)₅-CO-OC₂H₅ arrow CH₃(CH₂)₅CHO$CH_3(CH_2)_5-CO-OC_2H_5 \rightarrow CH_3(CH_2)_5CHO$	(I) CH₃MgBr, H₂O$CH_3MgBr, H_2O$
(B) C₆H₅COC₆H₅ arrow C₆H₅CH₂C₆H₅$C_6H_5COC_6H_5 \rightarrow C_6H_5CH_2C_6H_5$	(II) Zn(Hg)$Zn(Hg)$ and conc. HCl$HCl$
(C) C₆H₅CHO arrow C₆H₅CH(OH)CH₃$C_6H_5CHO \rightarrow C_6H_5CH(OH)CH_3$	(III) NaBH₄, H^+$NaBH_4, H^+$
(D) CH₃COCH₂COOC₂H₅ arrow CH₃CH(OH)CH₂COOC₂H₅$CH_3COCH_2COOC_2H_5 \rightarrow CH_3CH(OH)CH_2COOC_2H_5$	(IV) DIBAL-H, H₂O$H_2O$

Choose the correct answer from options given below:

Core Logic

The given reactant is p-hydroxybenzaldehyde, which contains both a phenolic -OH$-OH$ group (acidic) and an aldehyde group (electrophilic).

When one equivalent of Grignard reagent (PhMgBr$PhMgBr$) is added, it behaves primarily as a strong base due to the presence of an acidic proton. Acid-base reactions are extremely fast compared to nucleophilic additions.

The acidic phenolic -OH$-OH$ reacts with PhMgBr$PhMgBr$:

Upon workup with aq. NH₄Cl$aq. NH_4Cl$, the phenoxide ion simply regenerates the starting p-hydroxybenzaldehyde. However, the question asks for the number of hydroxyl groups present in the formed product (Benzene).

The distinct product formed in the reaction is Benzene. Benzene has 0 hydroxyl groups.

Pattern Recognition

Whenever a Grignard reagent encounters a molecule with an acidic hydrogen (alcohol, phenol, amine, alkyne), it will invariably act as a base first. If only 1 equivalent is used, nucleophilic addition to carbonyls will NOT happen.

Chapter Mix

Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids Class 12 Chemistry: Alcohols, Phenols and Ethers