Write the reaction equation: Fe-Fe2O3-FeCl3-Fe (OH) 3-Fe2 (SO4) 3-BaSO4

1) Iron reacts with oxygen, we get iron (III) oxide:

4Fe + 3O2 → 2Fe2O3;

2) Iron (III) oxide reacts with hydrochloric acid, resulting in the formation of iron (III) chloride and water:

Fe2O3 + 6HCl → 2FeCl3 + 3H2O;

3) When iron (III) chloride interacts with sodium hydroxide, during the above reaction, the formation of a precipitate of iron (III) hydroxide and sodium chloride is observed:

FeCl3 + 3NaOH → Fe (OH) 3 ↓ + 3NaCl;

Fe³⁺ + 3Cl^– + 3Na⁺ + 3OH^– → Fe(OH)₃↓ + 3Na⁺ + 3Cl^–;

Fe³⁺ + 3OH^– → Fe(OH)₃↓.

4) When the precipitate of iron (III) hydroxide and sulfuric acid interacts, we observe the formation of iron (III) sulfate and water:

2Fe (OH) 3 ↓ + 3H2SO4 → Fe2 (SO4) 3 + 6H2O;

5) Iron (III) sulfate reacts with barium hydroxide, resulting in precipitation of barium sulfate and iron (III) hydroxide.

Fe2 (SO4) 3 + 3Ba (OH) 2 → 3BaSO4 ↓ + 2Fe (OH) 3 ↓.