Question #44163

The theoretical dipole moment of $p$-nitroaniline, assuming no resonance interaction between the $\ce{-NH2}$ and $\ce{-NO2}$ groups, is calculated via vector addition to be $5.0\text{ D}$. The dipole moment of its pure charge-separated quinoid resonance structure ($\ce{H2N+ = C6H4 = NO2-}$) is estimated to be $25.0\text{ D}$. In benzene at $298\text{ K}$, the observed dipole moment of $p$-nitroaniline is $6.2\text{ D}$. When the solvent is changed to ethanol, intermolecular hydrogen bonding selectively stabilizes the charge-separated state, increasing its contribution to the resonance hybrid by an absolute value of $4.0\%$. Assuming the observed dipole moment is a linear combination of the non-interacting and quinoid forms, what is the observed dipole moment of $p$-nitroaniline in ethanol?