Multiple choice Which of the following salts is an example of double salt? Na2SO4 KCl CaSO4 KNaCO3 Reveal answer Fill a bubble to check yourself D Correct answer Explanation KNaCO3 (potassium sodium carbonate) is a double salt. Double salts are compounds that contain two different cations that crystallize together in a fixed ratio. The other options are simple single-cation salts.