Influence of a neutral component on the liquid-vapor coexistence and the surface tension of an ionic fluid

► The influence of a neutral component on the liquid-vapor coexistence and the surface tension of an ionic fluid is analyzed. ► As the fraction of neutral particles increases until 0.5, the growing repulsion in the system leads to higher vapor density. ► The surface tension and the estimated critical temperature of these mixtures are higher than those of the pure ionic fluid. ► For fractions of neutral particles greater than 0.5, the region of coexistence is reduced and the surface tension decreases.