In this work, data for liquid SnZn alloys with Na addition are presented. The thermophysical properties, viscosity, density and surface tension were measured using the discharge crucible method (DC). The experiments were conducted for Sn15Zn alloys with 0.1, 0.2, 0.5, 1.0, 3.0 and 5.0 at % Na. The measurements were performed over a temperature range of 548-823 K. The results show that the addition of Na to Sn15Zn (at. %) causes increased density and viscosity, and decreased surface tension in comparison to eutectic SnZn alloy. The new surface tension experimental data were compared with the corresponding values calculated by the Butler model, while the viscosity data were compared with models predicted values obtained by the Sichen-Boygen-Seetharaman, Seetharaman-Sichen, Kozlov-Romanov-Petrov, Kaptay and Gasior models, using thermodynamic input data. Correlation analysis between modelled and experimental data was performed. (C) 2015 Elsevier B.V. All rights reserved.