Chapter 22, Problem 18STP

To determine

To describe: The method of cleaning of dirty plates using a dishwashing liquid.

Explanation of Solution

Introduction: Soaps are basic salts. They contain weak acid and strong base. They are sodium salt of long chain carboxylic acids.

A dishwashing liquid is a soap solution. In a soap molecule, one end (carboxylic end) is hydrophilic in nature and the other end (hydrocarbon chain) is hydrophobic in nature. The dirt on plates contains oily particles. The hydrophobic end of the soap gets attached to the oil particles and hydrophilic part is attached to water molecules. After this action of salt, oil particles get suspended in the water and they get washed away from the plates.

This arrangement of hydrophobic and hydrophilic part of soap with oil particles and water results in the formation of micelle. In this arrangement, oil particles are at the center of the soap molecules with hydrophobic parts directed towards oil particles and hydrophilic parts away from the oil particles.

  

Conclusion: Thus, dishwashing solution or soap solution helps in removal of dirt from plates by the action of micelle formation.