Why are we getting a precipitate when we mix barium chloride and sodium hydroxide solutions? Barium hydroxide is supposed to be soluble.
Pure barium hydroxide is soluble (1.7 to 101.4 g / 100 mL at 0 to 80 degrees C)
Mixing fresh solutions, you will not get a precipitate BUT sodium hydroxide slowly reacts with the carbon dioxide in the atmosphere so that an older solution contains some carbonate ions.
Barium chloride has calcium as an impurity.
Both barium carbonate and calcium carbonate are insoluble.