wht is polar nd non polar??
When bond is formed between atoms of same element then bond pair of electron lies between these two atoms. Such a bond is called non polar bond and substances forming non polar bonds are called non polar substances. In non polar substances dipole moment is 0.
When bond is formed between atoms of different elements then bond pair lies towards the more electronegative atom.This electronegative atom attains negative charge while other atom attain positive charge. Such a bond is known as polar bond and substances forming these polar bonds are called polar substances. Polar substances have some value of dipole moment i.e their dipole moment is not equal to 0.
For example H2 is non-polar molecule but HCl is polar molecule.