Đáp án:

19.Fe3O4+H2SO4→FeSO4+Fe2(SO4)3+H2O

20.BaO+H2SO4→BaSO4↓+H2O

21.CaO+2HCl→CaCl2+H2O

22.Al2O3+HCl→AlCl3+H2O

23.Al2O3+2NaOH→2NaAlO2+H2O

24.2HCl+K2O→2KCl+H2O

25. giống câu 20

26.HCl+Fe2O3→FeCl3+H2O

27.H2SO4+Al2O3→Al2(SO4)3+H2O

28.2HCl+2NaOH→2NaCl+H2O

29.2HCl+2KOH→2KCl+H2O

30.2HCl+Fe(OH)2→FeCl2+H2O

31.6HCl+2Fe(OH)3→FeCl3+3H2O

32.2HCl+Ca(OH)2→CaCl2+H2O

33.H2SO4+Cu(OH)2→CuSO4+2H2O

34.H2SO4+2NaOH→Na2SO4+2H2O

35.H2SO4+2Fe(OH)3→Fe2(SO4)3+H2O

36.HNO3+Ba(OH)2→Ba(NO3)2+H2O

37.H2SO4(l)+Fe→FeSO4+H2

38.3H2SO4(l)+2Al→Al2(SO4)3+3H2

39.2HCl+Mg→MgCl2+H2

40.6HCl+2Al→2AlCl3+3H2

41.2NaOH+CO2→Na2CO3+H2O

42.NaOH+HCl→NaCl+H2O

43.2NaOH+H2SO4→Na2SO4+2H2O

44.3NaOH+FeCl3→Fe(OH)3↓+NaCl

45.6NaOH+Fe2(SO4)3→2Fe(OH)3↓+3Na2SO4

46.2NaOH+Cu(NO3)2→Cu(OH)2↓+2NaNO3

47.2NaOH+CuSO4→Cu(OH)2↓+Na2SO4

48.2NaOH+MgCl2→Mg(OH)2↓+2NaCl

49.6NaOH+Al2(SO4)3→2Al(OH)3↓+3Na2SO4

50.Ca(OH)2+CO2→CaCO3↓+H2O