(a) How do antiseptics differ from disinfectants ? Give one example of each. (Give two differences)
(b) Why do soaps not work in hard water ? (3 marks)
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(b) Hard water contains and ions. These ions form insoluble calcium and magnesium
salts respectively, when Na or K soaps are dissolved in hard water. These insoluble salt, sepa-
rate as scum which adheres to fabric, thereby making soap ineffective for cleansing action.