why is copper turn water blue
Answers. Best Answer: Copper Nitrate forms blue crystals which dissolve in water. Transition metal salts often form colored crystals. Since the other reaction product is metallic silver precipitate, and everyone knows what silver looks like, the blue is from the copper nitrate by process of elimination.The original solution was not blue because silver nitrate is colorless/slight gray when in solution and Cu(s) is just copper metal.ince the other reaction product is metallic silver precipitate, and everyone knows what silver looks like, the blue is from the copper nitrate by process of elimination.