Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Organic: Chemistry in Everyday Life

Question:

Select the incorrect statements(s)

A. Surface active agents like soaps and synthetic detergents form micelles in water.

B. Soaps are emulsifying agent

C. \(C_{17}H_{35}\) (hydrocarbon) and \(-COO^-\) (carboxylate) part of sterate ion \(C_{17}H_{35}COO^-\)both are hydrophobic

D. Surfactants are basic in nature

Choose the most appropriate answer from the options given below:

Options:

A and B only

C only

C and A only

D and B only

Correct Answer:

C only

Explanation:

The answer is 2. C only

The incorrect statement is \(C_{17}H_{35}\) (hydrocarbon) and \(-COO^-\) (carboxylate) part of sterate ion \(C_{17}H_{35}COO^-\)both are hydrophobic.

Let's break down the components:

1. Hydrocarbon Chain (\(C_{17}H_{35}\)):
The hydrocarbon chain, composed of carbon and hydrogen atoms, is indeed hydrophobic. Hydrophobic molecules are typically nonpolar and repel water.
In the case of stearate, the long hydrocarbon chain is hydrophobic, and this characteristic contributes to the molecule's overall hydrophobicity.

2. Carboxylate Group (\(-COO^-\)):
The carboxylate group (\(-COO^-\)) is hydrophilic. It contains an oxygen atom that is more electronegative than carbon and hydrogen, resulting in a polar covalent bond.
This polar nature of the carboxylate group makes it attracted to water molecules (hydrophilic) and facilitates the dissolution of stearate ions in water.

In summary, while the hydrocarbon chain is hydrophobic, the carboxylate group is hydrophilic. The combination of these two components in the stearate ion results in an amphiphilic molecule. Amphiphilic molecules have both hydrophobic and hydrophilic regions. In the case of stearate, this amphiphilic nature allows it to function as a surfactant, playing a role in the emulsification and solubilization of fats in water.