Chapter 17, Problem 17.67AP

(a)

Interpretation Introduction

Interpretation:

The functional groups present in the given fat molecule have to be identified.

Concept Introduction:

Functional group: They are certain substitutes in the organic molecules which are determine the characteristic reactions taking place in it.

Carboxylic acid: One $-OH$ group is attached to the carbonyl carbon atom of the compound. It is represented as $RCOOH$

Ester: One $-OR\text{'}$ group is attached to the carbonyl carbon atom of the compound. It is represented as $RCOOR\text{'}$. The hydrogen atom of $-COOH$ is replaced by an alkyl group.

Alkene: Unsaturated hydrocarbons having atleast one double bond between two carbon atoms are known as alkenes.

(b)

Interpretation Introduction

Interpretation:

The structure of the soap molecules produced in the given reaction has to be drawn.

Concept introduction:

Carboxylic acid: One $-OH$ group is attached to the carbonyl carbon atom of the compound. It is represented as $RCOOH$

Ester: One $-OR\text{'}$ group is attached to the carbonyl carbon atom of the compound. It is represented as $RCOOR\text{'}$. The hydrogen atom of $-COOH$ is replaced by an alkyl group.

Carboxylic acid salt: It is an ionic compound having a carboxylate acid anion and a metal cation. It is formed when a carboxylic acid and a strong base reacts giving water.

Carboxylic acid salts are written as name of cation in prefix and base name with “-oate” suffix.

Ester Hydrolysis: Ester hydrolysis can be caused by acid and base.

• Acid-catalyzed hydrolysis: In presence of strong acid such as ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$, ester reacts wither water to form the corresponding alcohol and carboxylic acid. it is the reverse of esterification.
• Saponification: Ester hydrolysis taking place in presence of base such as $NaOH$ or $KOH$ is known as saponification. Ester reacts with hydroxide ion forming carboxylic acid which again reacts with base resulting in the formation of a carboxylic acid salt.