Question:

Grignard reagents and organolithium compounds on addition to dry ice separately, followed by hydrolysis gives

Updated On: Jul 27, 2022
  • ketones and carboxylic acids respectively
  • carboxylic acids and ketones respectively
  • only carboxylic acids
  • only ketones
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

Lithium (EN $=1.0$ ) is less electronegative than $ Mg ( EN =1.2), $ therefore, organolithium compounds are more nucleophilic than Grignard reagents. As a result, organolithium compounds add more reactive $CO _{2}$ as well as less reactive resonance stabilised lithium salt of carboxylic acid thus formed to produce ketones.
Grignard reagents on the other hand, being less nucleophilic add only to the more reactive $CO _{2}$.
Was this answer helpful?
0
0

Questions Asked in AIIMS exam

View More Questions

Concepts Used:

Preparation

Preparation of Aldehydes:

  • In the presence of palladium catalyst spread on barium sulfate, Acid chlorides are reduced to aldehydes with hydrogen .
  • This is known as Rosenmund reduction. It is mostly used for the preparation of aromatic aldehydes.

Preparation of Ketones:

  • Acid chlorides on reaction with dialkyl cadmium form ketones. Grignard reagents are used in the preparation of Dialkyl cadmium.
  • 2R-Mg-X + CdCl2 → R2Cd + 2 Mg(X)Cl
  • 2RCOCl + R2Cd → 2R-CO-R + CdCl2
  • The mixed ketones are prepared very conveniently.

Preparation of Carboxylic Acids:

  • Primary alcohols are readily oxidized to carboxylic acids with common oxidizing agents such as potassium permanganate in neutral acidic or alkaline media or by potassium dichromate and chromium trioxide in acidic media.
  • RCH2OH → RCOOH
  • CH3(CH2)8CH2OH → CH3(CH2)8COOH

Read More: Aldehydes, Ketone, and Carboxylic Acids