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Aldehydes, Ketones and Carboxylic Acids appeared 46 times across 3 years — 5.3% of Chemistry. This question is from Name Reactions.

Year 2026 2025 2024 Total
Questions 14 21 11 46
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Match the LIST-I with LIST-II
List-I (Reagents)List-II (Name of Reaction involving carbonyl compound)
A. NH₂-NH₂, KOHI. Tollen's Test
B. Ag(NH₃)₂OHII. Clemmensen Reduction
C. Aq. CuSO₄, Sodium Potassium tartarate, KOHIII. Wolff-Kishner Reduction
D. Zn - Hg, HClIV. Fehling's Test
Choose the correct answer from the options given below

Solution & Explanation

Core Logic

(A) NH₂-NH₂ / KOH: Hydrazine with base is used in Wolff-Kishner Reduction to reduce carbonyls to alkanes. (A arrow III)

(B) [Ag(NH₃)₂]OH: Ammoniacal silver nitrate is Tollen's reagent, used in Tollen's Test to differentiate aldehydes from ketones. (B arrow I)

(C) Aqueous CuSO₄ + Sodium Potassium Tartrate + KOH: This is Fehling's solution (mixture of Fehling A and Fehling B). Used in Fehling's Test. (C arrow IV)

(D) Zn-Hg / HCl: Zinc amalgam with concentrated hydrochloric acid is the reagent for Clemmensen Reduction. (D arrow II)

Step 1: Final Matching

The correct matches are A-III, B-I, C-IV, D-II.

Pattern Recognition

Pure factual matching strictly based on NCERT name reactions and distinguishing tests for carbonyl compounds.

Chapter Mix

Class 12 Chemistry: Aldehydes Ketones and Carboxylic Acids

Reference Study Guides

Aldehydes Ketones And Carboxylic Acids

More Aldehydes Ketones and Carboxylic Acids Previous-Year Questions — Page 10

Q jee_main_2024_31_jan_morning Reactions with Grignard Reagent
The product of the following reaction is P.
Reactions with Grignard Reagent diagram for Q84 - JEE Main 2024 Morning
The image shows p-hydroxybenzaldehyde reacting with one equivalent of PhMgBr followed by aqueous ammonium chloride.
The number of hydroxyl groups present in the product P is
Numerical Answer. Answer: 0 to 0

Solution

Core Logic

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

When one equivalent of Grignard reagent (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 reacts with PhMgBr:

PhMgBr + HO-C₆H₄-CHO arrow Ph-H (Benzene) + BrMg-O-C₆H₄-CHO

Upon workup with aq. NH₄Cl, 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).

Reactions with Grignard Reagent diagram for Q84 - JEE Main 2024 Morning
The image shows p-hydroxybenzaldehyde reacting with one equivalent of PhMgBr followed by aqueous ammonium chloride.

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

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