- Soft Water is free from dissolved salts of such metals as calcium, iron, or magnesium, which form insoluble deposits such as appear as scale in boilers or soap curds in bathtubs and laundry equipment.
- Hard water is a term that denotes water having a very high mineral content (the term is the opposite of ‘soft water). As water percolates into deposits of calcareous, gypsum, or chalk that are primarily composed of carbonates of magnesium or calcium, bicarbonates, and sulfates, hard water is formed.
Classification of Hardness of Water
- Temporary Hardness of Water: Temporary hardness of water can be decreased by either boiling the water or by adding lime (also known as calcium hydroxide) via the lime softening process. The boiling of the water facilitates carbonate formation from bicarbonate and precipitates calcium carbonate from its solution. Finally, when the temporarily hard water is cooled after boiling, what is left behind is soft water.
- Permanent Hardness of Water: The permanent hardness of water is attributed to sulfates or chlorides of calcium and/or magnesium. Therefore, the factors that contribute towards the permanent hardness of water can be understood with the help of the following equation: Permanent hardness of the water sample = permanent hardness of the calcium component + permanent hardness of the magnesium component.
|Difference between Hard water and Soft water|
|It is rich in minerals||Contains very few elements|
|Soap is not so effective||Soap is easily effective|
|No foam and lather from soaps||Bubbly lather from soaps|
|Leaves spots on the washed dishes after they are dried||Does not leave any spots on dishes after they are dried|
|Contains minerals like magnesium and calcium||Contains sodium ion|
|Sometimes preferred drinking water||Sometimes not preferred drinking water|
|Ex: Groundwater like deep wells||Ex: Rainwater|
|Hair and skin become dry||Hair and skin become soft|