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Study Plan for Practical Work
In these exercises we have to use the observations we have made to deduce the identity of inorganic salts and organic functional groups. To do this you need to be familiar with both the organic tests and inorganic tests.
The best way to check your skills is to try some exercises. Have a look at the above links and then try to identify the organic functional group or inorganic salt.
Compound A
This is a white crystalline solid. The flame test gives a lilac flame. On treatment of a dilute solution of A with hydrogen peroxide solution a yellow colouration is seen. When hexane is added to the aqueous product and shaken it settles to give an upper purple layer.
Compound B
This is a pale green crystalline solid. When a solution of B is added to sodium hydroxide solution a gelatinous green precipitate is formed. A solution of B produces a white precipitate when added to barium chloride solution. This white precipitate is insoluble in acid. On heating a sample of the solid B a colourless liquid is seen condensing on the upper surfaces of the test tube.
Compound C
This is a white powder. The flame test produces a persistent orange-yellow flame. On addition of dilute hydrochloric acid rapid effervescence is seen. This gas turns limewater milky. A solution of C has a pH of 10.9.
Compound D
This is a white powder which gives a brick red flame test. On treatment of solid D with concentrated sulfuric acid a brown vapour is seen. A solution of B gives a pale yellow precipitate when treated with acidified silver nitrate solution.
Compound E
This is a white crystalline solid. On warming with dilute sodium hydroxide solution a gas is evolved which turn damp red litmus blue. Treatment with silver nitrate solution gives a white precipitate which is insoluble in dilute acid but which is readily soluble in dilute ammonia solution.
Compound F
This is a white crystalline compound which gives a yellow-green flame colour. On heating the solid strongly it melts and gives off a brown gas. The gas relights a glowing splint.
Compound G
This is a white powder which gives a lilac flame colour. On heating the solid melts and gives off a gas which relights a glowing splint. A solution of the residue from heating gives a pale yellow precipitate with acidified silver nitrate solution. This precipitate is insoluble in concentrated ammonia solution.
Compound H
This is a colourless liquid which burns with a luminous, sooty flame. On shaking with an orange solution of bromine water rapid decolourization is seen.
Compound I
This is a colourless liquid which effervesces readily on addition to sodium carbonate solution. A sample was warmed with sodium hydroxide solution and ethanol for a few minutes. The product was acidified and silver nitrate solution was added. A white precipitate was formed which dissolved in dilute ammonia solution.
Compound J
This is a colourless, neutral liquid. When a little solid phosphorus pentachloride is added steamy fumes are seen. When warmed with acidified sodium dichromate solution there is a colour change from orange to green. Oxidation of compound J with limited oxidizing agent yields a new organic compound K. Compound K turns warm Fehling's solution from blue to brick red.