Introduction / Context:
Soaps and detergents are among the most frequently tested everyday-chemistry topics. Recognizing the chemical class of soaps helps distinguish them from synthetic detergents and from neutral fats that precede their manufacture. The question focuses on the correct structural description of a typical soap molecule.
Given Data / Assumptions:
- Context: household soaps used for cleaning.
- Composition relates to fatty acid derivatives and alkali metals.
- Sodium and potassium are the common counter-ions.
Concept / Approach:
Soaps are formed by the alkaline hydrolysis (saponification) of triglycerides. The products are glycerol and the sodium or potassium salts of higher (heavier) fatty acids such as palmitate, stearate, or oleate. These ionic carboxylate salts act as surfactants, with hydrophilic head groups and hydrophobic tails, enabling emulsification of oils and dirt. They are not silicate salts, not mere mixtures of glycerol and alcohols, and not esters (those are the fats before hydrolysis).
Step-by-Step Solution:
Start from fats (triglycerides) + alkali → saponification.Products: glycerol + sodium/potassium carboxylate salts.These salts are the active “soaps.”Choose the option naming “sodium or potassium salts of heavier fatty acids.”
Verification / Alternative check:
Common labels list “sodium stearate,” “sodium palmate,” or “potassium oleate,” confirming the salt-of-fatty-acid identity.
Why Other Options Are Wrong:
Salts of silicates / sodium salts of mineral acids: Do not describe fatty acid soaps.Mixture of glycerol and alcohols: A byproduct plus generic alcohols—not soap.Esters of heavy fatty acids: Those are triglycerides (precursors), not soaps.
Common Pitfalls:
Confusing soaps (carboxylate salts) with detergents (sulfonates/sulfates) and with unreacted fats (esters).
Final Answer:
Sodium or potassium salts of heavier fatty acids
Discussion & Comments