NAME: Felix Saber

SAMPLE: Salicylic 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):

ca 0.01 g of your compound into a fusion tube. Take the fusion tube by tongs and bring it slowly
near the flame of a burner. Watch all consecutive changes of the appearance, colour and state.
Finally put the fusion tube directly into the flame and anneal it well.


Since my sample is an organic compound

Organic compounds- possible changes during heating and burning:

·         turning black, carbonization- EVERY TIME!

·         increasing of volume

·         melting

·         releasing vapours that are flammable

·         sublimation

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


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

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 (Prussianblue) 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

If the organic compound contains both nitrogen and sulphur, we must modify the procedure: Add a few
drops of dilute sodium hydroxide to 5 mL of the filtrate and then add ferrous sulphate solution
drop wise until the precipitate stops to form. Boil the mixture, filter it, acidify the filtrate by
adding dilute hydrochloric acid and finally add ferric chloride solution. A blue precipitate forms.

our sample gives positive reaction.

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.


our sample gives negative reaction

3.       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. Don’t throw the
precipitate away


our sample gives negative reaction


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

slightly soluble in water and it’s freely soluble in ethanol (96%)


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

acidic ,  The PH is between 3-4

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”):

So my sample is salicylic acid which is an organic compound and the formula is C7H6O3 so this
sample contains C,H,O so we go with flow chart 3 and from the Ph. Eur. we can say that this sample
is almost insoluble in water but can be freely soluble in ethanol and we have an acidic ph which is
roughly between 3-4 so based on the given flow chart we can identify that we have Salicylic acid

and since salicylic acid contains a phenolic –OH group gives positive reaction to Ferric chloride
which the reaction is described as below :

Dissolve ca 0.1 g of the compound in 10 mL of distilled water. Take 5 ml of the solution and add 1-
2 drops of ferric chloride solution. The solution turns blue- violet.

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

First identification : A,B

Second Identification: A,C

A.      Melting point : 158 C to 161 C

B.      Infrared absorption spectrophotometry

C.      Dissolve about 30mg in 5ml of 0.05 M sodium hydroxide, neutralise if necessary and dilute
to 20 ml with water R. 1ml of the solution gives reaction (a) which is “ to 1ml of the prescribed
solution add 0.5ml of ferric chloride solution R1. A violet colour is produced that persists after
the addition of 0.1 ml of acetic acid R’’ of salicylates