The structure of mixtures of dipolar hard sphere fluids with components of equal size but different dipole moments around a single ion is studied. The solvation energy and the polarization around the ion is obtained in the framework of the mean spherical approximation (MSA). Our theoretical results and the results of other workers are compared with simulation data obtained from Monte Carlo simulations. An interpretation of the meaning of preferential solvation is given in terms of the contrasting behaviors of partial polarization in the bulk and near the ion.