Almost 71 percent of the Earth’s surface is covered with water and the ocean consists of about 97 percent water and rest is occupied by rivers, ponds, and lakes.
What is Hard water
Hard water is formed when soft water combines with calcium and magnesium carbonates. It consists of ions and minerals whereas soft water doesn’t.
Hard water has moderate health benefits and good taste. However, it creates a lot of problems in daily activities like bathing because hard water does not produce foam with soap instead it forms insoluble scum.
This is due to the hardness in water due to ions.
Causes of Hardness of water
The hardness of water is caused by higher concentrations of multivalent cations. These ions are positively charged such as Ca2+ and Mg2+.
Rainwater initially is soft water and it becomes hard water after percolating through the limestone deposits.
The following reaction shows the formation of hard water:
CaCO3 (s) + CO2 (aq) + H2O (l) ⇌ Ca2+ (aq) + 2 HCO−3 (aq)
Temporary hardness is caused by the presence of dissolved calcium and magnesium bicarbonates. On dissolving, cations of calcium and magnesium (Ca2+, Mg2+) and anions of bicarbonates (CO2−3 and HCO−3) are formed.
Temporary hardness of water can be decreased by boiling or by the use of calcium hydroxide through the lime softening process.
Permanent hardness is caused by the presence of sulfates & chlorides of calcium and magnesium. This type of hardness can’t be easily removed just by boiling the water.
Instead, a water softener or ion exchange method can remove permanent hardness.
How to make Hard Water Soft?
Hard water can be made soft by using water softeners. These works by ion-exchange method which eliminates calcium and magnesium ions from water.
There are different types of Water softeners such as:
- Salt-based water softeners
These are the ion exchange type water softeners that are normally used.