Question

Why are detergents better cleansing agents than soaps?

Answer 1

Hint: We know that synthetic detergents are cleansing agents which possess all the properties of soaps but it does not contain any soap. There are many kinds of detergents namely anionic detergent, cationic detergent etc.

Complete step by step answer:
Here, we have to compare the qualities of soaps and detergents.

Let's first discuss soaps in detail. All soaps are manufactured by boiling oils or fats with soluble NaOH. Different types of soaps are manufactured by using different raw materials. The cleansing action of soap is not suitable for hard water. We know hard water contains magnesium and calcium ions. These ions produce magnesium and calcium soaps respectively in addition of potassium or sodium soaps in water.

$2{C_{17}}{{\rm{H}}_{{\rm{35}}}}{\rm{COONa}} + {\rm{CaC}}{{\rm{l}}_{\rm{2}}} \to 2{\rm{NaCl}} + {\left( {{{\rm{C}}_{{\rm{17}}}}{{\rm{H}}_{{\rm{35}}}}{\rm{COO}}} \right)_2}{\rm{Ca}}\,\,\left( {{\rm{insoluble}}\,{\rm{soap}}} \right)$

The formed insoluble soaps separate as scum in water and therefore soap is useless in hard water.

Let's discuss the cleansing action of detergents. As detergents do not contain any soap, so they can be used in both hard and soft water. The formation of foam will take place even in hard water. Moreover some detergents produce foam even in cold water.

So, we can say that detergents are better cleansing agents than soaps because they can be used in both hard and soft water. But, we cannot use soap in hard water.

Note: Always remember that using detergents has many environmental impacts. If the hydrocarbon chain of detergents is highly branched, then its degradation is not easy for bacteria. Due to this, detergents get accumulated. Effluent containing such detergents when disposed of in water bodies causes water pollution.