Determination of the Dipole Moment of Polar Compounds in Nonpolar Solvents G e o r g e M. Janini a n d Ali H. Katrib Kuwait University, Kuwait Dipole moments can give valuable information about the ohvsical structure of molecules. Most exoerimental . . chemistm handbooks descrihe experiments for the determination of the electric dipole moment of polar solutes in nonpolar solvents, h u t their procedures are unnecessarily complicated. We orooose a simole exoeriment hased on the orocedure of ~ u & e n h e i m( 1 ) and ~ m ' i t h(2) for the determination of the d i o d e moments of the isomeric comoounds. D-methoxvbenzGlidene-p-cyanoaniline and p-cyanobenzylidene-pmethoxyaniline. Although similar in chemical structure, size, and shape, the two compounds have different dipole moments. T h e difference is readily explained us in^ simple resonance structures that are already familiar to the itudents from basic organic chemistry courses. The experiment descrihed herehas heen used successfully a t Kuwait University in a physical chemistry laboratory. I t requires not more than a three-hour period.
Table 1. Dielectric Constants and Refractive Indices of Solutions In Benzene at 25'C C
c
mol c r r 3
'1
t-1
,,-I