The purpose of the work: to get acquainted with
the methods of discovering organic substances and their main elements.
Necessary equipment: some organic substance (aniline, its
chlorhydrates, thiomochevine, iodoform, sulfanylic acid), metal sodium, lead
nitrate, sodium nitroprussid, iron sulfate (II), chloroform or benzene.
№1-experience. Determination of sulfur, nitrogen, and halides in
Course of work: we put a few crystals or drops of our
detecting substance in a test tube. Place the test tube obliquely and place a
metal sodium from wheat grains, peeled from the shell, dried on filter paper,
heat the test tube in the horizontal direction first until the sodium melts,
and then hold it in the vertical direction until hot drops of sodium get into
the detecting substance. The mixture is strongly heated, put in a bowl with 5-6
ml of water and break the test tube. This practice is performed in a rack
grind the black particles of the mold, pour the liquid into a test tube and
heat it until it boils. By filtering the alkaline liquid, we observe the effect
on sulfur and nitrogen on halides. The liquid should be colorless.
determination of sulfur:
ml of lead nitrate is dripped with sodium hydroxide until the first formed
precipitate dissolves. Then we add a few alkaline liquids. The appearance of a
dark brown color or black precipitate of lead sulfide indicates the presence of
sulfur in our detected substance.
1-2 drops of sodium nitroprussid to 1 ml of alkaline liquid. If there is
sulfur, then the mixture quickly or gradually gives a bright purple color.
determination of nitrogen:
the alkaline liquid, we put a small crystal of iron cooperos, boil for 1-2
minutes, cool for 3-5 minutes and add liquefied hydrochloric acid. The
appearance of blue tincture of Berlin Azure indicates the presence of nitrogen.
determination of halides:
the alkaline liquid with nitric acid. Boil for a few minutes in a pull-out
cabinet. Allow to cool, add a few drops of silver nitrate. The appearance of a
heavy cotton precipitate indicates the presence of halogen. AgCl-White, MeBr -
yellow, MeJ - yellow. To determine if there is Br or J, we add 1 ml of
chloroform and add 1-2 drops of KMnO4 with a shake. Purple indicates that there
is a color - J, red indicates that there is a yellow-Br.
№2-experience. Determination of organic compounds carbon and
Course of work: 0.2-0.3 g of the determining substance in
glass is treated with 1 - 2 g of copper oxide (powder). The mixture is placed
in a dry test tube and firmly fixed with a cork with a gas-conducting tube. We
attach the test tube to the tripod in the horizontal direction. We insert the
end of the tube into a test tube with 2-3 ml of colorless lime or barite water.
The mixture is first simply heated more strongly after. We see that the
droplets on the cool walls of the test tube and tube form water and form carbon
dioxide, calcium or barium from the formation of a carbon dioxide precipitate.
№3-experience. The discovery of halides is the Beylstein reaction.
Working process: for a thin red copper wire, we make a
loop with a diameter of 1-2 and heat it up. We cool the blackened Wire, take
the object we identify with the hanger and hold it on the flame.
there is a halogen, then the flame will give a green color. To clean the wire,
we soak the hydrochloric acid and reheat it.
1. What is
the simplest way to distinguish an organic substance from an inorganic one?
2. How are
the elements in organic compounds qualitatively determined?
reaction occurred in barium hydroxide?
4. What is
the basis for the presence of carbon and hydrogen in organic matter, write a
5. What is
the essence of the Beylstein sample?
6. What are
the other ways to discover nitrogen in organic compounds?
Laboratory work№2 Topic: Qualitative reactions to organic compounds
Course of work: 0.2-0.3 g of the determining substance in glass is treated with 1 - 2 g of copper oxide (powder)