Themes for home preparation

Boron. A structure of atom. Oxidation degrees. Obtaining and properties of boron. Borides of metals, their types and properties. Hydroborons, obtaining, structure of molecules, properties. Hydroborides of metals, obtaining and properties. Boric anhydride, boron acids, their salts. Borax, boron carbide. Boron nitride. Application of boron and of its compounds.

Aluminium. A structure of atom. Oxidation degrees. Obtaining and properties of aluminium. The reactions of aluminium with water, acids and alkalis. Alumothermy. Oxide and hydroxide of aluminium, obtaining and properties. Salts of aluminium, their solubility, hydrolysis. Aluminates. Complexes. Alum. Hydride, carbide, nitride of aluminium.

Gallium, indium, thallium. A structure of atoms. Peculiarities of their positions in the periodic system compared with aluminium. Oxidation degrees. Obtaining of metals, their properties. Oxides and hydroxides of gallium (III), indium (III), thallium (III), obtainings and properties. Salts, their properties. Comparison of properties of gallium (III), indium (III), thallium (III) with properties of aluminium compounds.

Compounds of thallium (I).

Questions and tasks

1. How do р-elements of the ІІІ group react with acids and alkalis? Give the equations of the relevant reactions?

2. Give the reactions of the following oxides obtaining and explain the change of thermal stability in a range of oxides: B₂O₃ ®Al₂O₃ ®Ga₂O₃® In₂O₃® Tl₂O₃.

3. Calculate the formation heat of В2О3, if when interacting 50 g of boron with oxygen 2912,48 kJ had evolved.

4. Write down the equations of the reactions of hydroboron В₂N₆ obtaining. What properties do they have? What is the mechanism of chemical bond formation in В₂N₆ molecule?

5. Give the reactions of obtaining hydroxides Е(OH)₃ of р-elements of the Ш group. How and why do their acid-base properties change?

6. What occurs when neutralising orthoboric acid with sodium hydroxide solution? The salt of what acid is formed in this reaction?

7. What are the acid-base properties of boric acid caused by? Give the reactions of its sequential dehydration.

8. What are the peculiarities of borax hydrolysis and of its interaction with acids?

9. What alloys of aluminium are widely used in air engineering? What is this caused by?

10. What is the content of alumothermy? What metals can be obtained by alumothermic method?1

11. With what acids does aluminium react? Give the equations of the relevant reactions.

12. What structure does aluminium oxide have? How does it react with solutions of alkalis and acids, melts of alkalis and potassium hydrogen sulphate?

13. How are gallium, indium and thallium received in industry? How and why does the activity of these elements change?

14. How do gallium, indium and thallium react with acids? Give the equations of the relevant reactions.

15. How is thallium (I) salt converted in thallium (Ш) salt and vice versa? What oxidation-reduction properties do thallium (I) and thallium (ІІІ) compounds have?

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