The dipole moments of the 1-naphthoic acids and methyl 1-naphthoates substituted at various positions by a halogen or nitro group were measured in solution. The results are analysed in terms of the conformation of the carboxyl group, in particular, the rotational isomerism between planar s-cis and s-trans conformation of the carboxyl group in the 3-, 4-, 5-and 6-substituted derivatives.
