Question

How can polar covalent bonds become nonpolar?

Answer 1

Here's the reason for that.

Explanation:

I think, in certain cases all the polar covalent bonds of a certain molecule arrange themselves in such a geometry, that each of the polarities of the bonds cancel each other and the entire molecule thus becomes non-polar, since the net resultant moment of the entire molecule becomes zero.

For example, in carbon tetrachloride, the four polar `C-Cl` bonds are arranged in tetrahedral geometry and hence, the entire `C Cl_4` molecule is non-polar.