Chapter 23, Problem 68A

Interpretation Introduction

Interpretation:

The process by which structure of soaps makes them effective cleaning agents should be explained.

Concept introduction:

Soaps are potassium or sodium fatty acids which are obtained by the hydrolysis of fats in a chemical reaction. This reaction is known as saponification.

Explanation of Solution

The structure of soap is:

According to the structure of soaps, soaps contain both polar and non-polar ends.

Dirt or grease consist bonds between carbon atoms (just like non-polar end of soap) and it is oily in nature which doesn't dissolve in water. The nonpolar end of the soap that is carbon chain dissolves in dirt and the polar end of the soap dissolves in water. Therefore, soap molecules form a structure known as micelles. In micelles, one end (nonpolar) is directed towards the grease or dirt and the other end (polar) is directed outside. Thus, results in the formation of emulsion in water and this emulsion helps in dissolving the dirt or grease from clothes.

Hence, according to the property that is "Like dissolve like", the non-polar end (hydrocarbon) of the soap has ability to dissolves dirt or grease (carbon-carbon bonds) from the clothes.