5th prac)cal class IDENTIFICATION OF UNKNOWN DRUG
NAME: Lídia Prieto García
SAMPLE: Magnesium sulphate MgSO4
BEHAVIOUR OF COMPOUND DURING HEATING AND BURNING (describe what you should see during
the hea4ng of your sample in burner and choose one of possibility):
The sample it’s an inorganic compound so possible changes during hea)ng and burning are: no
changes, mel)ng to colourless liquid, which acquires the original colour a@er cooling down, change of
the colour, releasing vapours, sublima)on. But it never becomes carbonized and it won’t be burnt.
ORGANIC/INORGANIC/ORGANIC-INORGANIC COMPOUND
ELEMENTARY ANALYSIS (write down the reac4ons of tests you should do and mark which of them
should be posi4ve):
1. Nitrogen =nega)ve
C org+N org. CN
-


6 CN
+
Fe
2+
[Fe(CN)6]
4+
Fe
3+
[Fe(CN)6]
4+
Fe
3+
{Fe
III
[Fe
II
(CN)6]}
-
2. Sulphur = positive

Sorg. S2- 

S2- + Pb2+ PbS 

3. Halogens =nega)ve
Add silver nitrate.
4. Chlorine, bromide, iodine = nega)ve
AgCl + 2 NH3 [Ag(NH3)2]
+
Cl
SOLUBILITY
(decide according to the informa4on in Ph. Eur.): freely soluble in water, very soluble in
boiling water , prac)cally insoluble in ethanol 96%
pH of soluCon/suspension (decide according to nature of your sample): neutral
REACTIONS FROM THE FLOWCHARTS (write down your “flowcharts pathway”; describe results of
your hypothe4cal analysis – reac4ons from the flowcharts you can find in material called
“Iden4fica4on of an unknown drug”):
Unknown compound - inorganic compound - solubility in water : yes - Flowchart 1
5th prac)cal class IDENTIFICATION OF UNKNOWN DRUG
Inorganic compound soluble in water: no react with sodium hydroxide solu)on, not react with
amonium oxalate solu)on I, react with )tan yellow I = + Magnesium sulphate
IDENTIFICATION REACTIONS (from your monography choose the tests necessary for iden4fica4on of
your substance and describe them):
ReacCon of sulpfates:
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. It’s positive
Sorg. S2S2-
+ Pb2+ PbS
ReacCon of magnesium
Reaction with titan yellow solution I 

Dissolve about 0.1 g of the compound in 10 mL of distilled water. Take 3 mL of this solution,
add 1 mL of titan yellow solution and 1 mL of dilute sodium hydroxide. A red precipitate
forms => evidence of Mg 2+ .