Answer:
If the covalent is polar its means that pair of electrons are unequally shared between both atoms.
Through electronegativity difference.
Explanation:
Covalent bond:
It is the bond which is formed by the sharing of electrons between the atoms.
It is weaker than the ionic bond. The both bonded atoms do not completely transfer the electrons but can only shares.
For example:
The bond between the both chlorine atoms Cl₂ is coavlent. Cl:Cl
The bond between the H₂ atoms is covalent. H:H
The covalent bond can be polar or non polar. When it is formed between the atoms of two different elements then electronegativity difference is created. The atom atoms with high electronegativity values attract more strongly the shared pair of electron towards it self and become partial negative while the other became partial positive. Thus bond become polar.
But this is only in case when the electronegativity difference between both atoms is 0.4 are greater. If the difference is less than 0.4 than bond is non polar.
For example:
HCl, H₂O
The polar covalent bond is present in HCl and water because of greater electronegativity difference between hydrogen and chlorine , oxygen and hydrogen.
