Make up the equations o f the reactionss
B2O3 + Mg =
B + Mg =
Mg3B2 + HCl =
B2H6 + O2 =
B + O2 =
B2O3 + H2O =
B + HNO3 =
H3BO3
H3BO3 + NaOH =
Na2B4O7 + NaOH =
Na2B4O7 + H2SO4 + H2O =
Al + HCl =
Al + HNO3 (diluted) =
Al + NaOH + H2O =
Al + O2 =
Al + Fe3O4 =
Al2O3 + NaOH
Al
+ OH
=
Al(OH)3 + H =
Al(OH)3 + OH =
Al + S =
Al + N2 =
Ga2O3 + H2 =
In + O2 =
Tl + HNO3 =
Ga (In) + HCl =
Tl + HCl =
Ga + OH =
Tl2O3
Tl2O + H2O =
In(OH)3 + H =
Ga(OH)3 + OH =
Experimental section
1. Materials and equipment: metallic aluminium, aluminium foil, crystalline бурa, concentrated hydrochloric acid, sulfuric acid, nitric acid, solutions of litmus, sodium hydroxide, ammonia, soda, aluminium chloride, cobalt (ІІ) chloride, chrome (ІІІ) chloride, mercury (ІІ) nitrate, ethanol, test tubes, microspatula, glass rods.
2. Chemical properties of boron
2.1. Put 1-2 microspatulas of crystalline borax Na2B4O7 into a test tube, add some water and heat up until dissolution. Then add 2-3 drops of concentrated sulfuric acid and cool. What substance crystals are formed? Write down the equations of the relevant reactions.
2.2. Place 1-2 mls of distilled water into a test tube and add 4-5 drops of neutral litmus solution. Then put into the test tube few crystals of borax. What can you observe? Make the equations of borax hydrolysis.
2.3. Take nichrome wire with an eye on the end, heat it in the flame of a burner and immerse in crystalline borax. Then put the wire with borax again to the flame of the burner, melt borax, then immerse it in a solution of cobalt (ІІ) or chrome (ІІІ) salt and again calcinate in the flame of the burner. What can you observe? What processes proceed in the melt? Write down the equations of the relevant reactions.
2.4. Put 1-2 crystals of borax into a crucible, add 2-3 drops of concentrated sulfuric acid and 4-5 drops of ethanol, mix with glass rod and burn. What can you observe? In what colour is the flame coloured?
3. Chemical properties of aluminium
3.1. Put 1 granule of metal aluminium into each of three test tubes and add 5-10 drops: of 2 M hydrochloric acid solution into the first, of 1 M sulfuric acid solution into the second and of 2 M nitric acid solution into the third. What can you observe? Write down the equations of the reactions of aluminium with acids.
3.2. Put 1 granule of metal aluminium into a test tube and add 5-10 drops of 2 M sodium hydroxide solution. What can you observe? Write down the equations of the reactions of aluminium with alkalis interaction.
3.3. Scrape a slice of aluminium foil or wire with a sandpaper, put into a test tube and add 5-10 drops of concentrated nitric acid. Write down your observations.
2-3 minutes later pour acid off the test tube cautiously, wash out the metal with water, then add 5-10 drops of concentrated hydrochloric acid in the test tube. What can you observe?
3.4. Scrape a slice of aluminium foil or wire with a sandpaper, put in a test tube and add 5-10 drops of mercury (II) nitrate solution. One minute later pull it out and wash with water. What occurs with amalgamated aluminium on air? Immerse the same foil or wire into a test tube with water. What can you observe? Write down the equations of the reactions.
3.5. Place 4-6 drops of aluminium chloride solution into each of three test tubes and cautiously add in each 1-3 drops of 2 M sodium hydroxide solution until precipitate forms. Add 3-5 drops of 2 M hydrochloric acid solution into the first test tube, the same amount of 2 M sodium hydroxide solution into the second, and the same amount of 2 M ammonia solution into the third. What can you observe? Write down the equations of the reactions, which were taking place.
3.6. Add few crystals (or 2-3 drops of solution) of aluminium sulphate or nitrate into a test tube with neutral litmus solution. What can you observe? Write down the equations of the first stage of the hydrolysis.
3.7. Place 4-6 drops of aluminium chloride solution into a test tube and add 3-5 drops of 0,5N sodium carbonate solution. What can you observe? Then divide the content of the test tube in two parts and add 4-6 drops of 2 M hydrochloric acid solution to the first part, and 4-6 drops of 2 M sodium hydroxide solution to the second. What can you observe? Make a conclusion on chemical character of this substance.
Laboratory work 14
ELEMENTS of TITANIUM SUBGROUP
Themes for home preparation
Structure of atoms and oxidation states of titanium subgroup elements. Peculiarities of hafnium position in periodic system. Obtaining of titanium, zirconium and hafnium, their properties, reactions with acids. Oxides of titanium. Hydroxides and salts of titanium (IV), zirconium (IV), hafnium (IV). Salts of oxytitane and oxyzirconium. Titanates and zirconates. Compounds of titanium (III).
Carbides and nitrides of titanium and zirconium. Application of titanium, zirconium, hafnium and their compounds.
Questions and tasks
1. How do titanium subgroup elements react with acids and alkalis?
2. What simple substances titanium subgroup elements react with? Give the equations of the relevant reactions.
3. What the content of iodide method of titanium purification? What other metals can be purified in this way?
4. How do acid-base properties in the range TiO2 - ZrO2 - HfO2 change?
5. How are - and - titanium hydroxides received? Compare chemical properties of these compounds.
6. Explain, do ions Ti4+ exist in water solution? Why?
7. Why are titanium compounds with oxidation state less than four more stable, than those of zirconium and hafnium?