Question

Which of the following statement is not correct for soap ?
(1) One end of soap molecule is hydrophilic.
(2) When dissolved in water form micelles.
(3) Micelles of soap help in cleaning dirt from clothes.
(4) Sulphonate salts of long chain carboxylic acids.

Answer 1

ya the answer is option 4th only

Answer 2

Answer:

The answer is (4) Sulphonate salts of long-chain carboxylic acids

Explanation:

The other three options except the 4th are incorrect because soaps are manufactured from sodium or potassium salts of higher fatty acids such as stearic acid, palmitic acid, oleic acid, etc.

• The cleansing action of soaps and synthetic detergents is based on their ability to form micelles.

In solution, soap dissociates to give carboxylate ions( $RCOO^-$) and sodium ($Na^{+}$ ) ions.

• The carboxylate ion is composed of a nonpolar part ($R-$) of a long hydrocarbon chain called the tail and a polar part ($COO^{-}$), called the hydrophilic head.

• When you soak a dirty cloth in a soap solution, the hydrophobic tail section of the soap anion dissolves in the grease deposit and forms a micelle.

• The water-soluble carboxylate ions create a hydrophilic surface around the sphere, making the entire micelle of grease water-soluble.

• As an emulsifier, soaps aid in the formation of a stable emulsion of oil and water.

Finally, the soluble micelles are removed when the clothes are rinsed with water, and the cloth is dirt-free.