Water is an essential component of life and w/o it life is impossible. It covers about 71.4% of the Earth. Pure water has no smell, taste, or colour. Water can be found in solid, liquid or gaseous form. Water is regarded as a universal solvent. It is the only one whose solid form (ice) is lighter than its liquid form as it expands by 8% while freezing. Hard water
Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of calcium and magnesium-containing minerals such as limestone, chalk and dolomite. Soft Water
The water that lathers with soap easily is called soft water. It describes type of water that contain few or no minerals like calcium(Ca) or magnesium(Mg) ions. Water softening techniques
In this process, calcium and magnesium ions which are responsible for the hardness of water are made ineffective by treatment with sodium metaphosphate which is also known as calgon. The calgon forms a soluble complex with the ions. The water softened by this method is not fit for drinking but can be used for other purposes. Permutit process
It is a process where hard water containing ions such as Ca2+ is filtered through either a natural sand called Zeolite or manmade beads. In either case the Ca2+ ions and other hard water metallic ions are caught as they bond to the zeolite or beads. As this happens, Na+ ions are released from the zeolite and flush on into the water supply. Then after the zeolite becomes saturated with hard water ions, it is "renewed" by flushing it with a rich solution of NaCl where the excess Na+ ions go in and replace the hard water ions, flush them down the drain during the recharging cycles when the water softener is disconnected from the regular water supply. Ion exchange process
In this process both cationic and anionic impurities in water are removed. The procedure involves passing the hard water first through...
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