Question

Which of the following compound gives only primary alcohol on reaction with Grignard Reagent (RMgX)?

• A. \(\mathrm{CH_3CH_2CHO}\)
• B. \(\mathrm{HCHO}\)
• C. \(\mathrm{CH_3CH_2COCH_3}\)
• D. \(\mathrm{C_2H_5COCH_3}\)

Hint:

Shortcut yaad rakho: HCHO → 1° alcohol, aldehyde → 2°, ketone → 3° alcohol.

Answer 1

The Correct Option is B

Step 1: Grignard reaction rule.
Grignard reagent \(\mathrm{RMgX}\) carbonyl compounds ke saath react karta hai aur hydrolysis ke baad alcohol deta hai. Alcohol ka type carbonyl compound par depend karta hai.
Step 2: Important concept.

• Formaldehyde \(\mathrm{(HCHO)}\) → Primary alcohol
  
• Aldehyde (except HCHO) → Secondary alcohol
  
• Ketone → Tertiary alcohol
  

Step 3: Option analysis.

• (A) \(\mathrm{CH_3CH_2CHO}\): Secondary alcohol banega
  
• (B) \(\mathrm{HCHO}\): Sirf primary alcohol banata hai
  
• (C) \(\mathrm{CH_3CH_2COCH_3}\): Tertiary alcohol banega
  
• (D) \(\mathrm{C_2H_5COCH_3}\): Ye bhi ketone hai → tertiary alcohol
  

Step 4: Conclusion.
Isliye sirf formaldehyde hi primary alcohol deta hai.
Final Answer:\(\mathrm{HCHO}\).