The dipole moments of tetrahydropyran and dihydropyran have been obtained from measurements of dielectric constants of benzene solutions using a heterodyne beat method and following Hedestrand’s method of extrapolation for arriving at the value for total polarisation. The results obtained have been discussed in relation to the structure of these compounds.

Measurements of dielectric constants and densities of solutions of different concentrations of furoin and hydrofuramide in benzene as also refractive index measurements for hydrofuramide, have been carried out and the dipole moments of the above substances calculated from values of ‘P’ arrived at by the application of the Hedestrand’s method of extrapolation. The values of dipole moments of the two substances are: Hydrofuramide=2·66±·01 D. Furoin 3·24 D. The structures of furoin and hydrofuramide have been discussed from the experimentally obtained values and those calculated for various positions of furyl groups in the latter and furyl and hydroxyl groups in the former by the method of vector addition of moments.

In 0-3N acid the hydrolysis of chloroacetamide follows a bimole-cular law with an activation energy and activation entropy both greater than the corresponding quantities for acetamide in accord with predictions based on the charge distribution. However, at even slightly lower acidity the free energy of activation is a continuous function of the hydrogen-ion concentration becoming more positive with decreasing acidity in the range studied.

Dipole moment measurements have been made for the following formyl and acetyl derivatives, namely, formhydrazide, acethydrazide, acetaldoxime, acetoxime and formamidoxime in dioxan solution. The values obtained are 2·70, 3·15, 0·75, 0·88 and 2·24 (all in Debye units) respectively. The structure of the first four compounds have been discussed with particular reference to hyperconjugation. In the case of formamidoxime the results lead to an amidoxime structure.

Dipole moment measurements have been made for the following phenyl hydrazine derivatives of carbonic acid, namely diphenyl carbohydrazide, diphenyl carbazone and diphenyl thiocarbazone in dioxan solution. The values obtained are 3·77, 3·80 and 2·50 (all in Debye units) respectively. The structures of these compounds have been discussed with particular reference to resonance in these molecules.

Dipole moment measurements have been made in the case of a few aromatic hydrocarbon picrates, the values obtained being 2·18, 2·25, 2·97 (all in Debye units) for picrates of naphthalene, acenaphthene and phenanthrene respectively and the results discussed in terms of Mulliken’s theory. Measurements have also been extended to include a few salt-like heterocyclic amine picrates.

The dipole moments of three furan compounds studied in benzene solution indicate the hyperconjugation effect of the methyl group and the existtence of the alcohols primarily in thecis conformation (synclinal) with intramolecular hydrogen bonding involving the ring oxygen. The moments obtained are 0·72, 2·00 and 2·33 for the methyl, hydroxymethyl and the tetrahydrohydroxymethyl derivatives in the 2 position.