Propose a mechanism for the basic hydrolysis of benzonitrile to the benzoate ion and ammonia.

Verified step by step guidance

1. Identify the functional group in benzonitrile, which is the nitrile group ($-C\equiv N$).
2. Recognize that basic hydrolysis involves the reaction of the nitrile with hydroxide ions ($O{H}^{-}$).
3. In the first step, the hydroxide ion attacks the electrophilic carbon in the nitrile group, forming a tetrahedral intermediate.
4. The intermediate rearranges, leading to the formation of an amide intermediate and the release of ammonia ($N{H}_3$).
5. The amide intermediate undergoes further hydrolysis in the presence of hydroxide ions to form the benzoate ion ($C_6{H}_{5}CO{O}^{-}$).

Key Concepts

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In the case of benzonitrile hydrolysis, water acts as the nucleophile, attacking the carbon atom of the nitrile group, leading to the formation of an intermediate that eventually yields benzoate and ammonia.

Hydrolysis of Nitriles

Hydrolysis of nitriles involves the reaction of a nitrile with water, typically in the presence of an acid or base, to convert it into a carboxylic acid and ammonia. This process is crucial for understanding the transformation of benzonitrile into benzoate ion and ammonia, as it highlights the role of water in breaking the carbon-nitrogen bond and forming the carboxylate group.

Acid-Base Equilibrium

Acid-base equilibrium is essential in understanding the protonation and deprotonation steps during the hydrolysis reaction. In the case of benzonitrile hydrolysis, the benzoate ion can exist in equilibrium with its protonated form, benzoic acid, depending on the pH of the solution. This concept helps explain the final products and their stability in the reaction environment.