Chemical properties of oxygen compounds of sulfur

3.1. Put 6-8 drops of a sulfurous acid solution into each of three test tubes and add 2-3 drops: of bromine water into the first, of 0,5N potassium permanganate solution into the second, of hydrosulfuric acid solution into the third. What can you observe? What properties does sulfurous acid show in these reactions? Give the equations of the relevant reactions.

3.2. Place 6-8 drops of 0,5N solution of sodium sulphite into four test tubes and add: 2-3 drops of iodine water into the first, 5-6 drops of diluted sulfuric acid solution and 2-3 drops of 0,5N potassium permanganate solution into the second, 5-6 drops of diluted sulfuric acid solution and 2-3 drops of 0,5N potassium dichromate solution into the third, 5-6 drops of diluted sulfuric acid solution and 2-3 drops of 0,5N sodium sulphide solution in the fourth. What can you observe? What properties does sodium sulphite show in these reactions? Give the equations of the relevant reactions.

3.3. Place 5-8 drops of 1M sulfuric acid solution into each of three test tubes and add: microspatula of copper sawdust into the first, microspatula of iron dust into the second, microspatula of magnesium dust into the third. Does the reaction proceed in all test tubes? Explain the difference in interaction of these metals with diluted sulfuric acid. Give the equations of the relevant reactions.

3.4. Put some copper sawdust into 50 mls beaker and add 5-6 drops of a concentrated sulfuric acid. Put the beaker on a ring of a stand, laying an asbestos grid, and cautiously heat up. Put wet blue litmus paper above the beaker. On discolouration of litmus paper define, which gas evolves. Then stop heating, let the beaker cool, then put into it 8-10 drops of distilled water. What colour has a solution? Write down the equations of the relevant reactions.

3.5. Put a microspatula of zinc dust into a test tube and add 5-6 drops of a concentrated sulfuric acid. Anchor the test tube in a stand and heat on a small flame of the burner. After the appearing of gas bubbles in the test tube take with a pincers a filter paper, moistened with solution of lead salt above test tube. What can you observe? Give the equations of the relevant reactions.

3.6. Place 2-3 mls of concentrated sulfuric acid into two test tubes and add: a small slice of free sulfur into the first, a small slice of carbon into the other and cautiously heat to boiling. What can you observe? Give the equations of the relevant reactions.

3.7. Place 3-4 drops of concentrated sulfuric acid into two test tubes and add 2-3 crystals: of potassium bromide into the first, of potassium iodide into the other. What can you observe? Why? Give the equations of the relevant reactions.

3.8 Place 6-8 drops of 0,5N solution of sodium thiosulphate into a test tube and add 3-4 drops of diluted sulfuric acid solution. What can you observe? Why? Give the equations of the relevant reactions.

3.9. Place 2 mls of chlorine water into a test tube and add 2 drops of 0,5N solution of sodium thiosulphate and 1-2 drops of 0,5N solution of barium chloride. What can you observe? Add some solution of barium chloride to a solution of sodium thiosulphate in another test tube. Compare obtained results and explain them. Give the equation of the reaction.

3.10. Place into two test tubes 1 ml: of bromine water into the first, of iodine water into the second and add drop by drop 0,5N sodium thiosulphate solution until the discoloration. Then put 1-2 drops of methyl orange solution into both test tubes. In what case is the indicator discoloured? Compare obtained results and explain them. Give the equations of the relevant reactions.

3.11. Dissolve crystalline potassium persulphate in water. Measure рH of an obtained solution with the help of рH-meter, then heat it up until boiling. Measure pH value once more after cooling. Compare obtained results and explain them. How and why does the value of рH change?

3.12. Place 3-4 drops of 0,5 M solution ammonium persulphate solution, 1 droplet of 2N sulfuric acid solution, 2 drops of silver nitrate solution into a test tube, heat up the mixture, and then pour by glass rod droplet (as small as possible, as, if the concentration of ions Mn²⁺ is too great, a precipitate of Mn(OH)₂ forms instead of ions MnO^-₄) of 0,5 N manganese (ІІ) sulphate solution. What can you observe? What role do the ions of silver (I) play? Give the equation of the reaction.

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