One of the ways of increasing the ecological and economic performance of internal combustion engines is the addition of small amounts of hydrogen to hydrocarbon fuel. We used the differential capillary method to measure the capillary constant a(2) and to determine the surface tension sigma of ethane/hydrogen mixtures. Experiments were conducted in the temperature range from 93.15 to 283.15 K at pressures from that of the phase equilibrium of pure ethane to 4 MPa. The values of a(2) and sigma as functions of the temperature, pressure and concentration of hydrogen are described by analytical dependences. The effect of the nature of the substance being dissolved and the nonideality of the forming mixture on the value of its surface tension has been examined. (C) 2017 Elsevier Ltd. All rights reserved.