What are polar & non polart covalent bond ???

Depending on the relative electronegativities of the two atoms sharing electrons, there may be partial transfer of electron density from one atom to the other. When the electronegativities are not equal, electrons are not shared equally and partial ionic charges develop.

The greater the electronegativity difference, the more ionic the bond is. Bonds that are partly ionic are called polar covalent bonds.

Nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.