Iron, cobalt, nickel

Themes for home preparation

The characteristics of d-elements of VIII group.

Iron. The structure of atom, oxidation states. Occurrence in nature. Obtaining of cast iron and steel. Physical and chemical properties of iron. Oxide, hydroxide and salts of iron (II): obtaining and properties. Reducing properties of iron (II).

Oxide, hydroxide and salts of iron (III): obtaining and properties. Complexes of iron.

Compounds of iron (VI): ferrates, their properties.

Cobalt, nickel. The structure of atoms, oxidation states. Obtaining of cobalt and nickel, their properties. Oxides, hydroxides, salts of cobalt (II) and nickel (II), their obtaining and properties. Oxide of cobalt (III), hydroxides of cobalt (III) and nickel (III), their obtaining, interaction with acids. Complexes of cobalt and nickel.

Application of iron, cobalt, nickel and their compounds. Comparation of properties of iron, cobalt, nickel and of their compounds.

Questions and tasks

1. What chemical processes occur when obtaining cast iron?

2. What is the essence of convertor and Martin processes of steel obtaining? What chemical processes these methods are based on?

3. Why does the stability of compounds with an oxidation state of + 2 increase, and of those with an oxidation state of + 3 decrease in a range Fe - Co - Ni?

4. Write the equations of the chemical reactions, which proceed when iron corrodes.

5. How do iron, cobalt and nickel react with sulfuric and nitric acids?

6. By what reactions is it possible to obtain oxides and hydroxides of iron (II), cobalt (II) and nickel (II)? Describe their acid-base properties.

7. Compare the composition and stability of ammonia and cyanide complexes of iron (II), cobalt (II) and nickel (II).

8. By what reactions is it possible to obtain oxides and hydroxides of iron (IІI), cobalt (ІII) and nickel (ІII)? Describe their acid-base properties.

9. What volume of chlorine at the temperature of 0° and at the pressure of 101,3 kPa is necessary to oxidise 1 ton of 24% potassium hexacyanoferrate (II) solution?

10. What oxidation state is the most stable in ordinary compounds and in complexes: а) of iron, b) of cobalt with strong field ligands?

11. Why is iron (ІІІ) iodide not obtained? Give the equation of the chemical reaction, which will proceed when mixing the relevant solutions.

12. How is potassium ferrate obtained? How does it react with sulfuric acid? Give the equations of the relevant reactions.

Make up the equations o f the reactions

Fe₂O₃ + H₂ =

Fe + O₂ =

Fe₂O₃ + CO =

Fe + Cl₂ =

Fe + HNO₃ =

Fe(OH)₂ + O₂ + H₂O =

FeSO₄ + KMnO₄ + H₂SO₄ =

Fe₂O₃ + Na₂CO₃

FeCl₃ + Cu =

FeCl₃ + KI =

FeCl₃ + K₄[Fe (CN)₆] =

FeCl₂ + K₃[Fe (CN)₆] =

FeCl₃ + KCNS =

Na₂FeO₄ + H₂SO₄ =

Na₂FeO₄ + NH₄OH =

Co + HNO₃ =

Co + O₂ =

Ni + O₂ =

Co(OH)₂ + O₂ + H₂O =

CoCl₂ + Br₂ + NaOH =

Ni(OH)₃ + HCl =

Co(OH)₃ + H₂SO₄ =

Co(NO₃)₂

NiSO₄ + NH₃ =

Experimental section

1. Materials and equipment: iron sawdust, soft steel plate, crystalline sodium hydroxide, elementary bromine, solutions of hydrochloric acid, acetic acid, ammonium - iron (ІІ) sulphate (Mohr's salt), iron (ІІ) sulphate, iron (ІІІ) sulphate, iron (ІІІ) chloride, nickel (ІІ) sulphate, cobalt (ІІ) chloride, copper (ІІ) sulphate, sodium hydroxide, sodium carbonate, ammonia, dimethylglioxyme, potassium hexacyanoferrate (ІІ), potassium hexacyanoferrate (ІІІ), potassium iodide, potassium thiocyanate, sodium nitrite, bromine water, hydrogen peroxide, concentrated hydrochloric acid, sulfuric acid, nitric acid, porcelain crucible, 100 mls beakers, test tubes, glass rods.