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प्रश्न
Which of the following compounds is used for water softening?
पर्याय
\[\ce{Ca3(PO4)2}\]
\[\ce{Na3PO4}\]
\[\ce{Na6P6O18}\]
\[\ce{Na2HPO4}\]
उत्तर
\[\ce{Na6P6O18}\]
Explanation:
Sodium hexametaphosphate \[\ce{(Na6P6O18)}\], commercially called ‘calgon’, is used to remove hardness from water.
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संबंधित प्रश्न
What is meant by ‘demineralised’?
Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?
how can demineralised be obtained?
The oxide that gives \[\ce{H2O2}\] on treatment with dilute \[\ce{H2SO4}\] is ______.
When sodium peroxide is treated with dilute sulphuric acid, we get ______.
Hardness of water may be temporary or permanent. Permanent hardness is due to the presence of:
(i) Chlorides of \[\ce{Ca}\] and \[\ce{Mg}\] in water.
(ii) Sulphates of \[\ce{Ca}\] and \[\ce{Mg}\] in water.
(iii) Hydrogen carbonates of \[\ce{Ca}\] and \[\ce{Mg}\] in water.
(iv) Carbonates of alkali metals in water.
Discuss briefly de-mineralisation of water by ion exchange resin.
Match the items in Column I with the relevant item in Column II.
| Column I | Column II |
| (i) Hydrogen peroxide is used as a | (a) zeolite |
| (ii) Used in Calgon method | (b) perhydrol |
| (iii) Permanent hardness of hard water is removed by | (c) sodium hexametaphosphate |
| (d) propellant |
Which one of the following methods is most suitable for preparing deionized water?
100 ml of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalent of CaCO3 is ______.
[Molar mass of calcium bicarbonate is 162 g mol-1 and magnesium bicarbonate is 146 g mol-1)
