Question

One of the two compounds in $NOF$ and $N{O}_{2}F$ has a resultant dipole moment of $\mu =1.81D$ and the other has a resultant dipole moment of $\mu =0.47D$. Regarding these compounds, which of the following is correct?

• A. $1.81D$ for $N{O}_{2}F$ and 0.47 D for $NOF$
• B. $0.47D$ for $N{O}_{2}F$ and $1.81D$ for $NOF$
• C. For both $N{O}_{2}F$ and $NOF$ dipole moment, $\mu =1.81D$
• D. For both $N{O}_{2}F$ and $NOF$ dipole moment, $\mu =0.47D$

Answer 1

The correct option is B $0.47D$ for $N{O}_{2}F$ and $1.81D$ for $NOF$

Fluorine is the most electronegative and oxygen is more electronegative than nitrogen.

In $NOF$, the bond dipole moments will add up while the lone pair are in the opposite direction. Since the lone pair has a less impact on the net dipole moment, we see significant dipole moment in NOF.

The dipole moment in $NOF$ will be more than in $N{O}_{2}F$ since the former has a bent shape and the latter has a trigonal planar shape. The trigonal planar shape is more symmetrical which decreases its dipole moment.