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Question Question 20
Differentiate between -
(a) Hard & soft water
(b) Temporary & permanent hard water
with examples.
(a) Differences between Hard and soft water:
| Hard water | Soft water |
|---|---|
| Water is said to be hard when it does not lather readily with ordinary soap. | Water is said to be soft when it lathers readily with ordinary soap. |
| Hard water contains dissolved calcium & magnesium salts, e.g. calcium and magnesium bicarbonates, sulphates and chlorides. | Soft water does not contain dissolved calcium & magnesium salts. |
| Sources of hard water include natural water i.e., water from springs and rivers. | Sources of soft water include rain water and distilled water. |
(b) Differences between temporary and permanent hard water:
| Temporary hard water | Permanent hard water |
|---|---|
| Temporary hard water is one whose hardness can be removed by boiling. | Permanent hard water is one whose hardness cannot be removed by boiling. |
| It is due to the presence of calcium & magnesium bicarbonates Ca(HCO3)2, Mg(HCO3)2. | It is due to the presence of calcium, magnesium, chlorides and sulphates [CaCl2, MgCl2, CaSO4, MgSO4]. |