Question

The net dipole moment is zero in:

• A. $PB{r}_{2}C{l}_3$
• B. $PB{r}_{3}C{l}_2$
• C. $S{F}_4$
• D. $IC{l}_5^{-}$

Answer 1

The correct option is B $PB{r}_{3}C{l}_2$


If two identical dipole vectors are oriented at ${180}^{\circ }$ to each other, they cancel each other results in zero net dipole moment. If three identical dipole vectors are oriented at ${120}^{\circ }$ to each other, they cancel each other results in zero net dipole moment.
Among the molecules given, in $PC{l}_{2}B{r}_3$ two $P-Cl$ bonds are oriented at ${180}^{\circ }$ to each other and three $P-Br$ bonds are oriented at ${120}^{\circ }$ to each other. Hence the net dipole moment is zero .