Осуществите превращения Cu---CuO---CuSo4---Cu(OH)2---CuCl2
2Cu + O2 = 2CuO CuO + H2SO4 = CuSO4 + H2O CuSO4 + 2NaOH = Cu(OH)2 + Na2SO4 Cu(OH)2 + 2HCl = CuCl2 + 2H2O