Question

Reagent "P" in the given reaction is :

• A. $LiAlH_4$
• B. $NaBH_4$
• C. DIBAI-H
• D. $OH^-$

Answer 1

Answer: (D)

$OH^-$

Answer 2

The given reaction involves the conversion of glycerol triacetate (a triester) into glycerol (a triol) and acetate ions. This transformation is a hydrolysis reaction, specifically the base-catalyzed hydrolysis of an ester, also known as saponification. In this process, the ester bond is cleaved by a nucleophilic attack of a hydroxide ion ($OH^-$) on the carbonyl carbon, leading to the formation of an alcohol and a carboxylate salt.

• $LiAlH_4$ (Lithium Aluminum Hydride): This is a strong reducing agent that reduces esters to primary alcohols, not acetate ions.

• $NaBH_4$ (Sodium Borohydride): This is a milder reducing agent that typically reduces aldehydes and ketones but generally does not reduce esters.

• DIBAI-H (Diisobutylaluminum hydride): This is a reducing agent that can reduce esters to aldehydes or primary alcohols, not acetate ions.

• $OH^-$ (Hydroxide ion): A hydroxide ion, typically supplied by a strong base like NaOH or KOH, is the characteristic reagent for the base-catalyzed hydrolysis (saponification) of esters.

Therefore, reagent "P" is $OH^-$.