Question

For which of the following molecules $\Delta \mu \ne 0$

• A. Only I
• B. I and II
• C. Only III
• D. III and IV

Answer 1

Answer: (D)

$-OH$ Group and $-S-H$ group have not linear geometries so they cannot cancel each other and net dipole moment is positive. Hence III and IV polar, in I and II $\mu$ cancel each other so ${\mu }_{net}$ is zero and they are non-polar.