Water Softening
- Hard water can be softened by removing the calcium and magnesium ions
- There are many advantages to this such as not wasting soap when washing
- Using soft water is also important in many industrial processes because the ions contained in hard water can interfere with the chemical processes
- There are three methods used to remove 'hardness' from water:
- Boiling
- Adding washing soda (sodium carbonate)
- Using an ion exchange column
- Boiling water removes the calcium and magnesium ions from temporary hard water
- Washing soda is used to wash clothes and can soften permanent and temporary hard water
- When washing soda is added to hard water, a reaction takes place that removes the calcium and magnesium ions
- Ion-exchange columns remove calcium and magnesium ions by replacing them with sodium ions and are used in domestic water-softening units
- This method also removes hardness from temporary and permanent hard water
Summary Table of Advantages & Disadvantages
Method | Advantages | Disadvantages |
Boiling |
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Washing soda |
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Ion-exchange columns |
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Examiner Tip
If you are studying for the foundation paper, you only need to be able to name the methods used to soften hard water and the pros and cons of each one.