The sodium or potassium salts of which acid are defined as soaps?

Question

Question

This question was previously asked in

RRB Technician Grade III Official Paper (Held On: 29 Dec, 2024 Shift 3)

Answer 1

The correct answer is Carboxylic acid.

Key Points

Soaps are defined as the sodium or potassium salts of fatty acids, which are a subcategory of carboxylic acids.
Carboxylic acids have the general formula R-COOH, where R is a hydrocarbon chain.
In the soap-making process called saponification, triglycerides react with sodium hydroxide (NaOH) or potassium hydroxide (KOH) to form glycerol and the sodium or potassium salts of the fatty acids.
The carboxylate end of the soap molecule is hydrophilic (water-attracting), while the long hydrocarbon chain is hydrophobic (water-repelling), which helps in emulsifying oils and greases in water, allowing them to be washed away.
Common examples of fatty acids used in soap making include stearic acid, palmitic acid, and oleic acid.

Additional Information

Sulphuric acid
- Sulphuric acid (H₂SO₄) is a strong mineral acid used in various industrial processes such as fertilizer production, petroleum refining, and chemical synthesis.
- It is not used in soap making due to its strong acidic nature and inability to form salts with fatty acids.
Nitric acid
- Nitric acid (HNO₃) is another strong mineral acid used primarily in the production of fertilizers, explosives, and in metal processing.
- It does not react with fatty acids to form soaps.
Hydrochloric acid
- Hydrochloric acid (HCl) is a strong acid used in metal cleaning, food processing, and the production of chlorides.
- It does not participate in the soap-making process.