4) Raspuns corect d) Na₂O, MgO, SrO Na₂O+H₂O=2NaOH MgO+H₂O=Mg(OH)₂ SrO+H₂O=Sr(OH)₂ 5) CuSO₄+2KOH=Cu(OH)₂+K₂SO₄ CuSO₄+Ba(OH)₂=Cu(OH)₂+BaSO₄ Cu(NO₃)₂+H₂S=CuS+2HNO₃ Cu(NO₃)₂+Ba(OH)₂=Cu(OH)₂+Ba(NO₃)₂