Question

Match List - I with List - II. 

• A. (A)-(IV), (B)-(III), (C)-(I), (D)-(II)
• B. (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
• C. (A)-(I), (B)-(III), (C)-(II), (D)-(IV)
• D. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

Hint:

The reactions listed here are all methods of forming aldehydes from different starting materials such as nitriles, chlorobenzene, and acyl chlorides. Familiarity with reagents and reaction conditions helps in correctly identifying the reaction type.

Answer 1

The Correct Option is A

Step 1: Analyze Each Reaction in List-I

Option (A): RCN (i) SnCl₂, HCl → RCHO (ii) H₃O⁺

This reaction is the reduction of a nitrile (RCN) to an aldehyde (RCHO). The first step involves the reduction of the nitrile group using stannous chloride (SnCl₂) in the presence of hydrochloric acid (HCl), followed by hydrolysis to form the aldehyde. This reaction is a classic example of the Stephen reaction (IV).

Option (B): C₆H₅CHCl → C₆H₅CHO

This reaction involves the reduction of a chlorobenzene (C₆H₅CHCl) to a benzaldehyde (C₆H₅CHO). The reaction uses hydrogen in the presence of palladium (Pd) and barium sulfate (BaSO₄) as a catalyst. This reaction is known as the Rosenmund reduction (III).

Option (C): C₆H₅CH₃ (i) CrO₃, CS₂ → (ii) H₂O

This reaction involves the oxidation of toluene (C₆H₅CH₃) to benzaldehyde. The first step uses chromium trioxide (CrO₃) as an oxidizing agent, followed by hydrolysis to form the aldehyde. This reaction is known as the Etard reaction (I).

Option (D): CO, HCl → C₆H₅CHO

This reaction involves the formation of benzaldehyde from chlorobenzene (C₆H₅Cl) in the presence of carbon monoxide (CO) and hydrochloric acid (HCl), with the catalyst being anhydrous AlCl₃ or CuCl. This reaction is known as the Gatterman–Koch reaction (II).

Step 2: Match the Reactions with Their Names

Based on the analysis of the reactions above, we can now match the reactions with their corresponding names from List-II:

• (A) RCN (i) SnCl₂, HCl → RCHO (ii) H₃O⁺ → (IV) Stephen reaction
• (B) C₆H₅CHCl → C₆H₅CHO → (III) Rosenmund reduction
• (C) C₆H₅CH₃ (i) CrO₃, CS₂ → (i) H₂O → (I) Etard reaction
• (D) CO, HCl → C₆H₅CHO → (II) Gatterman–Koch reaction

Step 3: Conclusion

The correct matching of List-I with List-II is:

• (A) → (IV) Stephen reaction
• (B) → (III) Rosenmund reduction
• (C) → (I) Etard reaction
• (D) → (II) Gatterman–Koch reaction

This matches the correct answer.