ICSE BoardEnglish MediumSTD 9CHEMISTRYPractical Work3 Marks
Question
Compare the effect of soaps and detergents on hard water.
✓
Answer
Water that contains Ca2+ and $Mg^{2+}$ ions is called hard water. When soap is added to hard water, insoluble compounds form which appears as sticky scum. This scum leaves a deposit on clothes, skin, and hair. You could have a ring around the collar. Detergents have replaced soap for many cleaning jobs around the home.
The development of synthetic detergents by chemists was a great advantage for people with relatively hard tap water in their homes.
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