Sodium sulfate plus barium chloride?
sodium chloride and barium sulfate
Barium sulfate is much less soluble in water than either of sodium chloride and sodium chloride. When mixed, the solubility of the barium sulfate is exceeded. The barium sulfate then precipitates as fine solids, which remain suspended but scatter light to produce the milky look. Added: Na+ (sodium ion) and Cl- (chloride ion) don't react, Only Ba2+ and SO42- do so by forming precipitate: SO42- + Ba2+ --> (BaSO4)s