Question

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

• A. ketones and carboxylic acids respectively
• B. carboxylic acids and ketones respectively
• C. only carboxylic acids
• D. only ketones

Answer 1

Answer: (B)

carboxylic acids and ketones respectively

Answer 2

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 $CO _{2}$.