The saponification of an alkanoate to produce soap and alkanol involves

Analysis of the Question

The question asks for the chemical process involved when an alkanoate (specifically an ester, like a fat or oil) reacts to produce soap and an alkanol (alcohol).

Concept Explanation

Saponification is the alkaline hydrolysis of an ester (typically a triglyceride, which is a fat or oil).

In this process:

1. Reactants: An ester (alkanoate) reacts with a strong base (like Sodium Hydroxide, NaOH, or Potassium Hydroxide, KOH).
2. Reaction: The base breaks the ester bonds.
3. Products: The reaction yields a salt of a fatty acid (which is soap) and an alcohol (alkanol, usually glycerol).

The term "hydrolysis" comes from "hydro" (water) and "lysis" (splitting). In saponification, the ester is split by the action of the hydroxide ions in the presence of water.

Step-by-Step Solution

1. Identify the reaction type: Saponification is defined as the alkaline hydrolysis of fats and oils.
2. Examine the options: • A. Dehydration: This is the removal of water molecules from a compound. This is not the primary mechanism of saponification. • B. Esterification: This is the reverse of saponification. It is the reaction between an alkanoic acid and an alkanol to form an ester and water. • C. Hydrolysis: This is the chemical breakdown of a compound due to reaction with water (or hydroxide ions). Since saponification involves breaking the ester bond to form soap and alcohol, it is a form of hydrolysis. • D. Oxidation: This involves the loss of electrons or an increase in oxidation state. This is not the mechanism for soap formation.

Conclusion

Since saponification is specifically the alkaline hydrolysis of an ester, the correct process is hydrolysis.

Exam Tip

Think of Saponification as the "breaking down" of an ester. Whenever you see "splitting" or "breaking" a complex molecule using water or a base, think Hydrolysis. Remember: Esterification builds the ester; Hydrolysis (Saponification) breaks it down!