Copper sulfate+sodium hydroxide = copper hydroxide+sodium sulfate
But in some places where the concentration of sodium hydroxide is low, another relatively light-colored precipitate is basic copper sulfate:
2 cuso 4+2 NaOH = Cu2(OH)2so 4+na2so 4
Basic copper sulfate is easy to decompose, and black copper oxide will appear if heated;
Cu2(OH)2 SO4 (thermal) = CuO+CuSO4+H2O