The alkanol obtained from the production of soap is

Analysis

The question asks for the specific alkanol (alcohol) produced as a byproduct during the process of soap making, which is chemically known as saponification.

Concept Explanation

Saponification is the alkaline hydrolysis of fats and oils (triglycerides). Fats and oils are esters formed from a long-chain fatty acid and a trihydric alcohol called glycerol (also known as propane-1,2,3-triol).

When a fat or oil reacts with a strong base (like sodium hydroxide, NaOH), the ester bonds are broken. The fatty acid part reacts with the sodium ion to form soap (sodium salt of fatty acid), and the alcohol part is released as a byproduct.

The general reaction is: Fat/Oil + Sodium Hydroxide → Soap + Glycerol

Step-by-Step Solution

1. Identify the reactants: Fats and oils are esters of fatty acids and glycerol.
2. Understand the reaction: During saponification, the ester linkage is cleaved.
3. Identify the products: The reaction produces soap (the salt of the fatty acid) and the alcohol that was originally part of the fat molecule.
4. Determine the alcohol: Since fats and oils are triglycerides, the alcohol released is always glycerol. Glycerol is a polyhydric alcohol (specifically a triol) with the formula $C_3H_8O_3$.

Comparing this to the options:

• Propanol is a monohydric alcohol.
• Ethanol is a monohydric alcohol.
• Glycerol is the trihydric alcohol produced in this process.
• Methanol is a monohydric alcohol.

Conclusion

Exam Tip

Remember the "Saponification Rule": Fats/Oils = Soap + Glycerol. Whenever you see a question about soap production, look for "Glycerol" or "Glycerin" as the alcohol byproduct. Don't be confused by the term "alkanol"—while glycerol is a polyhydric alcohol, it is the standard answer for this specific chemical process in JAMB chemistry.