Question

Explain why is o=c=o nonpolar while r-o-r is polar

Answer 1

The hybridization of CO2 is sp. It has a linear shape with zero lone pair, hence applying the law of vectors, the two vectors (both having their heads towards oxygen) cancel each other (so zero dipole moment, ie, nonpolar).

In ethers, the shape is angular or bent or v shape with two lone pairs of oxygen. Since all the vectors are not equal here hence they do not cancel each other, so no zero dipole moment and hence it's polar.