what is polar and non polar
A polar molecule is the one in which there is some separation of charge in the chemical bonds, so that one part of the molecule has a slight positive charge and the other a slight negative charge, i.e., the molecule has a permanent electric dipole. Water is a well-known example of polar molecule.
A non-polar molecule is the one in which the electrons are distributed more symmetrically and thus does not have an abundance of charges at the opposite sides. The charges all cancel out each other.