The MNDO method has been used to calculate the electronic and energetic characteristics of nitrobenzene, o-, m- and p-nitrochlorobenzenes, aniline and o-, m- and p-chloroaniline molecules. For the case of the hydrogenation of the given compounds in the presence of palladium catalysts it has been shown that the rate of the reaction increases with increasing effective negative charge on the nitro group of the substrate.