Chemical properties of sulfur and of its hydrogen compounds

2.1. Collect oxygen by the method of water replacement in a 100 mls flask so that approximately 10 mls of water remains in the flask. Burn some sulfur on iron spoon and put it into the flask. Compare burning of sulfur on air and in oxygen. On expiration of reaction shake the flask. Define the reaction of medium, adding 3-5 drops of litmus solution to the flask. Make a conclusion on properties of obtained oxide.

2.2. Put 1-2 microspatulas of free sulfur into a dry test tube and heat to boiling slowly. What can you observe? Then pour liquid sulfur off in cold water, pull out obtained mass from water and dry between sheets of a filter paper. What properties does plastic sulfur formed have?

2.3. Put 1-2 microspatulas of iron Fe sulphide into a test tube, add 2-3 mls of dilute hydrochloric acid, close with a stopper with an exhausting tube and cautiously heat up. Burn the gas, which evolves from the exhausting tube. What is the colour of the flame? Keep the bottom of a dry cold beaker above the flame. What can you observe? Give the equations of the relevant reactions.

2.4. Put 5-6 drops of fresh hydrosulfuric acid solution into each of three test tubes and add 5-6 drops: of chlorine water into the first, of bromine water into the second, of iodine water into the third one. What can you observe? Give the equations of the relevant reactions.

2.5. Place 4-6 drops of solutions of potassium chloride, of iron (ІІ) sulphate, of zinc sulphate, of manganese (ІІ) sulphate, of cadmium sulphate, of lead nitrate and of copper sulphate into seven test tubes and add 3-4 drops of hydrosulfuric acid solution to each one. Define, in what test tubes the precipitates were formed. Add 2-3 drops of a sodium sulphide solution to solutions, in which precipitates were not formed. Write down the observations, indicating colour of precipitates. Add 3-5 drops of nitric acid solution to all precipitates. What can you observe? Give the equations of the reactions, which have taken place.

2.6. Measure with the help of рH-meter the value of рH of sodium sulphide solution. Explain the value of pH.

2.7. Place 4-6 drops of sodium sulphide solution into each of three test tubes and add 3-4 drops of solutions: of aluminium sulphate into the first, of chrome (ІІІ) nitrate into the other. What can you observe? Give the equations of the relevant reactions.

2.8. Place 4-6 drops of 0,5N sodium sulphide solution, 3-4 drops of diluted sulfuric acid into a test tube and add some crystals of sodium sulphite. Mix the solution with a glass rod. What can you observe? Give the equation of the reaction.

2.9. Put 3-4 drops of 0,5N potassium permanganate solution, 6-8 drops of diluted sulfuric acid into a test tube and add 5-6 drops of 0,5N sodium sulphide solution. What can you observe? What properties does sodium sulphide show in this reaction? Give the equation of the reaction.

2.10. Put 3-4 drops of 0,5N solution of potassium dichromate, 6-8 drops of diluted sulfuric acid into a test tube and add sodium sulphide solution until complete discoloration of the solution. Why is the solution discoloured? What substance precipitates? What properties does sodium sulphide show in this reaction? Give the equation of the reaction.

2.11. Put 3-4 drops of bromine water solution and 6-8 drops of hydrosulfuric acid solution into a test tube. What can you observe? What properties does hydrogen sulphide show in this reaction? Give the equation of the reaction.

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