\(\left(1\right)CuO+2HCl\rightarrow CuCl_2+H_2O\\ \left(2\right)CuCl_2+2KOH\rightarrow Cu\left(OH\right)_2\downarrow+KCl\\ \left(3\right)Cu\left(OH\right)_2+H_2SO_4\rightarrow CuSO_4+2H_2O\\ \left(4\right)CuSO_4+BaCl_2\rightarrow CuCl_2+BaSO_4\downarrow\)