Explanation

(a)
The molecule in which the bond dipoles of all the bonds are cancel out by each other, is called non – polar e.g., $CCl_{4}$.
In $CCl_{4}$, there is a large difference between the electronegativities of C and Cl but all the four $C - Cl$ bond dipoles cancel each other , hence it is a non-polar molecule.
[image:4_image71.emf]