Copper oxalate (CuC₂O₄) is considered to be insoluble in water. It has very low solubility, which means that only a small amount will dissolve in water at room temperature. The solubility product constant (Ksp) for copper oxalate is quite low, indicating that it does not readily dissolve in aqueous solutions. In practical terms, this means that when mixed with water, copper oxalate will primarily remain as a solid rather than entering into