The correct order of acidic strength of the major products formed in the given reactions, is:
Acidic Strength Of Carboxylic Acids diagram for Q65 - JEE Main 2026 Evening
Reactions producing A, B, C, and D products for acidity comparison.
Choose the correct answer from the options given below:

Solution & Explanation

Core Logic

Identify the major products [A], [B], [C], and [D]:

(A) PhNH₂ 1) NaNO₂ + HCl PhN₂^+Cl^- 2) CuCN PhCN 3) H₃O^+ PhCOOH (Benzoic acid)

(B) CH₃CH₂CHO [Ag(NH₃)₂]^+, OH^- CH₃CH₂COOH (Propanoic acid)

(C) CH₄ + O₂ Mo₂O₃ HCHO Na₂Cr₂O₇/H^+ HCOOH (Formic acid)

(D) PhCH₂MgBr + CO₂ H₃O^+ PhCH₂COOH (Phenylacetic acid)

Step 1: Compare Acidity

Acidic Strength Of Carboxylic Acids diagram for Q65 - JEE Main 2026 Evening
Reactions producing A, B, C, and D products for acidity comparison.
Acidity order: Formic acid > Benzoic acid > Phenylacetic acid > Propanoic acid. HCOOH (C) has no +I alkyl group, making it the strongest. PhCOOH (A) has an sp² carbon attached directly, which is mildly electron withdrawing via -I relative to alkyls. PhCH₂COOH (D) has an sp³ methylene spacer, so -I from phenyl is weakened. CH₃CH₂COOH (B) has a purely electron-donating ethyl group (+I effect), making it the weakest.

Step 2: Final Conclusion

Order is C > A > D > B.

Pattern Recognition

HCOOH is stronger than PhCOOH. Aliphatic acids with +I groups are the weakest.

Chapter Mix

Class 12 Chemistry: Carboxylic Acids Class 12 Chemistry: Amines Class 12 Chemistry: Aldehydes, Ketones and Carboxylic Acids

Reference Study Guides

Carboxylic Acids

More 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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