9. Soap powder and scouring soaps These contain a scouring agent( abrasive) such as powdered pumice or finely divided sand and builders like sodium carbonate and trisodium phosphate. Builders make the soaps act more quickly.
Disadvantages of Soaps
Soap is good cleansing agent and is 100 % biodegradable microorganisms present in sewage water can completely oxidise soap to CO2, As a result, it does not create any pollution problem. However soaps have two disadvantages:
( i) Soaps cannot be used in hard water since calcium magnesium ions present in hard water produce curdy precipitates of calcium and magnesium soaps.
These insoluble soaps separate as scum in water and causes hinderance to washing because the precipitate adheres onto the fibre of the cloth as gummy mass. Thus, a lot of soap is wasted if water. is hard.
( ii) Soaps cannot be used in acidic solutions since acids precipitate the insoluble free fatty acids which adhere to the fabrics and thus, reduce the ability of soaps to remove oil and grease from fabrics.