NAME: Filippos Chatzittofi  F16190

SAMPLE:  Ascorbic Acid

BEHAVIOUR OF COMPOUND DURING HEATING AND BURNING (describe what you should see during the heating
of your sample in burner and choose one of possibility):



turning black, carbonization- EVERY TIME!

·         increasing of volume

·         melting

·         releasing vapours that are flammable

·         sublimation



An organic compound will be burnt without a rest (it can leave a black coating on inner sides of a
fusion tube, because of insufficient access of the air).


                      -------ORGANIC----/INORGANIC/ORGANIC-INORGANIC COMPOUND

ELEMENTARY ANALYSIS (write down the reactions of tests you should do and mark which of them should
be positive):

HALOGENS (HALIDES)

Acidify a portion (5 mL) of the filtrate with dilute nitric acid, and if nitrogen and/or sulphur

are present, boil for 1 - 2 minutes. Cool and add aqueous silver nitrate.

Formation of a heavy, white, yellowish or yellow precipitate of silver halide indicates halogen.

Should be negative

1. NITROGEN (CYANIDES)

To a portion (5 mL) of the filtrate add a few drops of ferrous sulphate solution and a few drops of
ferric chloride solution. Boil the mixture for half a minute, cool and acidify by adding dilute
hydrochloric acid drop wise. Formation of a bluish-green precipitate (Prussian blue) or a blue
solution indicates that the original substance contains nitrogen. If no precipitate appears, allow
to stand for 15 minutes, filter and inspect filter paper.

Corg. + Norg. CN-

6 CN- + Fe2+ [Fe(CN)6]4-

[Fe(CN)6]4- + Fe3+ {FeIII[FeII(CN)6]}-

Should be negative


2. SULPHUR (SULPHIDE)

To the cold filtrate (5 mL) add a few drops of lead acetate solution.

Production of a black solution or a black precipitate indicates that the original substance
contains sulphur.

Sorg. S2-

S2- + Pb2+ PbS

Should be negative

No Sulphur no halides and no halogens present.



SOLUBILITY (decide according to the information in Ph. Eur.):

·         Freely soluble in water, sparingly soluble in ethanol

pH of solution/suspension (decide according to nature of your sample):

·         2.1-2.6  solution

REACTIONS FROM THE FLOWCHARTS (write down your “flowcharts pathway”; describe results of your
hypothetical analysis – reactions from the flowcharts you can find in material called
“Identification of an unknown drug”):



 Identification of an organic compound containing C, H, O

 It is soluble in water and Is acidic .

 Ascorbic acid or Citric acid or Tartaric acid




IDENTIFICATION REACTIONS (from your monography choose the tests necessary for identification of
your substance and describe them):

First identification: B, C

Second identification: A, C, D

A.      Ultraviolet and visible absorption spectrophotometry


Test solution: Dissolve 0,10g in water R and dilute immediately to 100.0ml with the same solvent.
Add 1.0ml of the solution to 10ml of a 10.3g/L solution of HCL R and dilute to 100.0ml  with water
R.


B. Infrared absorption spectrophotometry

     C. pH   (2.2.3): 2.1 to 2.6 for solution S

Solution S : dissolve 1,0g in carbon dioxide free water R and dilute to 20 ml with the same
solvent.

D. To 1ml of solution S add 0.2ml of dilute nitric acid R and 0.2ml of silver nitrate solution R2.
A grey precipitate is formed.