Production of acetylene hydrocarbons and their chemical properties

                   № 5 Laboratory work

       Production of acetylene hydrocarbons (ethins)        and  their chemical properties

The purpose of the work: the experimental production of acetylene and the study of the chemical properties of acetylene.

Reagents and equipment: calcium carbide, potassium permanganate solution, bromine water, 1% alcohol solution of phenolphthalein, glass tubes, gas tube stopper, 0.2 N silver nitrate solution, ammonia solution of copper (I) chloride.

Experiment 1. Acetylene production and its properties  

Procedure: Put a piece of calcium carbide (CaC2) in a test tube equipped with a gas tube and add 3-4 drops of water. Calcium carbide in the test tube reacts with water to form acetylene.

        СаС2 + 2Н2О → Са (ОН) 2 + НС ≡ СН

 Ignite the acetylene coming out of the gas tube at the end of the tube, which will glow with a bright pink flame. Then immerse the end of the gas tube in a test tube filled with a solution of potassium permanganate (a solution oxidized with sulfuric acid). Perform the same experiment with a solution of bromine water, a solution of copper (I) chloride in ammonia, a solution of silver (I) diamine hydroxide.Prepare a solution of silver (I) diamine hydroxide as follows: pour 2 drops of silver nitrate solution into a test tube and add a few drops of concentrated ammonia solution (until the precipitate of silver (I) oxide formed). When the separation of acetylene is complete, add 1 drop of an alcoholic solution of phenolphthalein to the test tube.

 The equation for the reaction to obtain acetylene should be written using its structural formula.

Questions for self-monitoring and protection of laboratory work:

1. Write the equation of the combustion reaction of acetylene.

2. What happens when acetylene is passed through a solution of potassium permanganate? Write the reaction equation, use the method of electronic balance (the reaction releases carbon dioxide, manganese and potassium sulfates, water).

3. What change is observed when acetylene is passed through bromine water? Write the reaction equation.

 4. Explain the change in color of the solution when adding phenolphthalein solution to the original test tube.

5. Write the equation for the reaction of acetylene with a solution of copper (I) chloride in ammonia.