The effects of sodium (Na) on hydrogen chloride (HCl) hydrate diffusion in ice were investigated using infrared laser resonant desorption depth-profiling (LRD) techniques. By exciting the O-H stretching vibration in H2O, LRD was used to depth-profile into ice sandwich multilayers containing either an HCl or a Na/HCl interlayer. Diffusion coefficients for HCl were determined by measuring the relaxation of die HCl concentration gradient versus time. The HCl hydrate diffusion coefficient at 190 K in pure ice was D = 5.1(+/-1.7) x 10(-11) cm(2)/s and lower for the Na/HCl interlayers. The HCl diffusion coefficients varied from D = 1.2(+/-0.5) x 10(-11) cm(2)/s to D less than or equal to 9.0 x 10(-11) cm(2)/S for initial interlayer molar ratios of Na/Cl = 0.04 to Na/Cl = 0.5, respectively. The effect of Na on HCl hydrate diffusion in ice is attributed to anion-cation trapping. Similar trapping interactions may influence the distribution of species in ice cores used to interpret the historical record of Earth's atmosphere.