Oxidative conversion of methane, ethane, propane, benzene, hydrogen and their binary mixtures R1-R2-N2O-He (where R1, R2 are substances under study) were studied on HZSM-5 at 350-450 degrees C. Relative reactivities were estimated, rate of conversion of hydrocarbons correlating with the strength of C-H bond. C-13 label distribution in the product of (CH4)-C-13-C6H6-N2O feed was studied by GC-MS, H-1 and C-13 NMR. It was shown that methane was capable to alkylate the aromatic ring under reaction condition, giving toluene and xylenes from benzene.