Hard & Soft Water – Ways to Softening of Hard Water


Water is generally clear and transparent but minerals and the concentration of chemicals make it soft or hard water. Soft water produces a good lather with soap and hard water does not. Hard water contains chlorides and sulphides of magnesium and calcium. Therefore, water dissolves many salts of divalent cations like Mg2+, Ca2+, and anions like Cl-, SO42-, HCO3-. Hardness is of two types.

Temporary hardness is due to the presence of bicarbonates of calcium and magnesium. Permanent hardness is due to sulphates and chlorides. Temporary hardness can be treated by boiling and Clark’s method. Permanent hardness can be treated by washing soda and by using sodium zeolite.

Chemical Bonding: Ionic Bond & Metallic Bond


Universally everything tends to be more stable. Atoms gain stability by attaining the electronic configuration of noble gases. The 2 or 8 electrons in the valence shell represent the stability of the atom.

So, the atom follows the duplet rule, attaining 2 electrons or octet rule, attaining 8 electrons in the valence shell. They acquire stability by sharing electrons, obtaining electrons, or giving electrons.  So, for this purpose atoms have different types of chemical bonding.

The chemical bond is basically the force of attraction between atoms that holds them. Chemical bonds are of four types 1) Ionic bond 2) Covalent bond 3) Metallic bond and 4) Coordinate Covalent Bond.