The reagent(s) used for softening the temporary hardness of...

The reagent(s) used for softening the temporary hardness of water is (are) [2010]
(a) $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(b) $\mathrm{Ca}(\mathrm{OH})_{2}$
(c) $\mathrm{Na}_{2} \mathrm{CO}_{3}$
(d) $\mathrm{NaOCl}$

Key Concepts

Temporary Hardness

Temporary hardness is mainly due to the presence of bicarbonate ions in water, which combine with calcium and magnesium to form soluble bicarbonate salts. This type of hardness can be removed by processes such as boiling or by using chemical reagents that convert the bicarbonates into insoluble precipitates.

Precipitation Reactions in Water Softening

In the context of water softening, precipitation reactions are used to remove hardness by converting soluble ions into insoluble compounds that can be filtered out. The addition of an appropriate reagent initiates a reaction that transforms the dissolved minerals into a solid form, thereby reducing the concentration of hardness-causing ions in the water.

Water Hardness

Water hardness refers to the presence of dissolved minerals, particularly calcium and magnesium ions, which can cause scaling in pipes and reduce the effectiveness of soaps and detergents. It is typically classified into temporary and permanent hardness based on the chemical composition of the dissolved salts.

Chemical Reagents in Water Softening

Chemical reagents are substances added to water to react with hardness-causing ions. In the case of temporary hardness, reagents that can convert bicarbonate salts into insoluble carbonates are used. This concept involves selecting an appropriate chemical, such as sodium carbonate, which precipitates the calcium and magnesium ions as their respective insoluble carbonate salts.

Transcript

Please give Ace some feedback