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प्रश्न
Why does the hardness of water render it unfit for use in a washing purposes.
उत्तर
If hard water is used, calcium and magnesium ions of the water combine with the negative ions of the soap to form a slimy precipitate of insoluble calcium and magnesium usually called soap curd (scum).
Formation of soap curd will go on as long as calcium and magnesium ions are present. Till then, no soap lather will be formed and cleaning of clothes or body will not be possible. Moreover, these precipitates are difficult to wash from fabrics and sometimes form rusty spots if iron salts are present in water.
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संबंधित प्रश्न
What do you mean by solubility of a solute in a solvent ?
What is the importance of dissolved salts in water?
Explain why boiled or distilled water tastes flat.
Explain why:
The solute cannot be separated from a solution by filtration.
In which of the following substances will there be
Decrease in mass
In which of the following substances will there be
No change in mass when they are exposed to air?
Sodium chloride
Iron
Conc. sulphuric acid
Table salt
Sodium carbonate crystals
What is the advantage of a detergent over soap?
Give a reason why water is called a ‘universal solvent’ but, an alkali is not.
Give a reason for the following.
Water is a universal solvent.
What insoluble substance? Give examples.
