Question

Assertion
$C{O_2}$ is non polar while $S{O_2}$ is polar molecule.
Reason
$S - O$ bonds are polar while $C - O$ are non polar.
A.Both assertion and reason are correct and reason is the correct explanation for assertion
B.Both assertion and reason are correct but reason is not the correct explanation for assertion
C.Assertion is correct but reason is incorrect
D.Assertion is incorrect but reason is correct

Answer 1

Carbon dioxide is a linear molecule while sulfur dioxide is a bent molecule. Both molecules contain polar bonds, but carbon dioxide is a nonpolar molecule while sulfur dioxide is a polar molecule. It contains two polar bonds that are arranged symmetrically. Carbon forms a double bond with each oxygen atom. But the geometry of carbon dioxide is linear so that the two bond dipole moments cancel and there is no net molecular dipole moment.

Complete answer:
$C{O_2}$ is a linear molecule so the resultant dipole moment is zero since the individual dipole moments of the $CO$ bond cancel each other. Whereas, $S{O_2}$ is an angular molecule due to which it has a net dipole moment. Hence $SO$ is polar and $CO$ is non- polar. $C{O_2}$ is a linear molecule and the oxygen atoms on each end are symmetrical . Whereas the $S{O_2}$ molecule is bent shaped and is polar because of the electronegativity difference between Sulphur and oxygen . Resulting in a net dipole moment . This doesn't occur in $C{O_2}$ molecule hence its non polarity .
$CO$ is polar in nature because of the difference in electronegativity of carbon and oxygen atoms. The carbon and oxygen atom have unequal charge distribution and therefore
$CO$ bond has a net dipole moment making $CO$ a polar molecule. The $S - O$ bond in $S{O_2}$ is polar since there is an electronegativity difference between the sulfur and oxygen atoms.
So, the correct answer is (C) Assertion is correct but reason is incorrect.

Note:
To determine the polarity of a covalent bond using numerical means, find the difference between the electronegativity of the atoms; if the result is between 0.4$0.4$ and $1.7$, then, generally, the bond is polar covalent. If there are no polar bonds, the molecule is nonpolar.