Chapter 15, Problem 97A

Interpretation Introduction

Interpretation: To give the reason when molecules of dirt and grease are lifted from the cloth fibers.

Concept Introduction: Detergent consists of two parts that are head and tail parts. When detergent molecules aggregate in water, they form organized structures which are known as a micelle.

Answer to Problem 97A

Detergents are added to it that contain surfactants which are useful in reducing the surface tension and also can work effectively. These surfactants act as emulsifiers and help in removing the dirt from the fibers.

Explanation of Solution

When detergent molecules aggregate in water, they form organized structures which are known as a micelle. The micelle is formed when detergent is added to water. The two parts of the detergent molecule dissolve in different mediums.

The particles of dirt and grease cannot be removed by water due to the surface tension of water. Therefore, detergents are added to it that contain surfactants which are useful in reducing the surface tension and also can work effectively. These surfactants act as emulsifiers and help in removing the dirt from the fibers.

Conclusion

Thus, detergents are used for removing dirt from clothes.