Detection of nitrogen, sulphur, halogens and phosphorus in an organic compound is done by:
Nitrogen, Sulphur, and halogens present in organic compounds are detected by Lassaigne’s test. Here, a small piece of Na metal is heated in a fusion tube with the organic compound.
In case both nitrogen and sulphur is present in an organic compound with sodium fusion extract a blood red colour is formed that is of:
When a compound is heated with copper(ii) oxide it is the test for:
The correct answer is Option C.
When a compound is heated with copper(ii) oxide it is the test for carbon.
These are detected by heating the compound with copper(II) oxide. Carbon is oxidized to CO2 – confirmed by reaction with lime water that gives turbidity and turns limewater milky. Hydrogen is oxidized to H2O – tested with anhydrous copper sulphate which turns blue.
Laissaigne’s extract is made to:
The correct answer is option C
The halogens, nitrogen and sulphur are covalently bonded to the organic compounds. In order to detect them, the elements need to be converted into their ionic forms. This is done by fusing the organic compound with sodium metal. The ionic compounds formed during the fusion are extracted in aqueous solution and can be detected by simple chemical tests. The extract is called sodium fusion extract or Lassaigne's extract.
In sulphur estimation, 0.157 g of an organic compound gave 0.4813 g of barium sulphate. The percentage of sulphur in the compound is:
A compound when treated with sodium peroxide and the solution is boiled with nitric acid and then treated with ammonium molybdate is the test for:
The phosphorus containing organic compound are detected by 'Lassaigne's test' by heated with an oxidizing agent (sodium peroxide)
The phosphorus present in the compound in oxidised to phosphate.
The solution is boiled with nitric acid and then treated with ammonium molybdate to produced canary yellow precipitate.
Na3PO4 + 3HNO3 ⟶ H3PO4 + 3NaNO3
H3PO4 + 12(NH4)2MoO4 (Ammonium molybdate) + 21HNO3⟶(NH4)3PO4⋅12MoO3↓ + 21NH4NO3 + 12H2O
The white precipitate which is formed in the detection of chloride ion is due to the formation of:
If silver nitrate solution is poured into a solution of sodium chloride, a chemical reaction occurs forming a white precipitate of silver chloride.
In Carius method of estimation of halogen, 0.15 g of an organic compound gave 0.12 g of AgBr. The percentage of bromine in the compound is:
Mass of Bromine = 80u
Mass of AgBr = 188u
Weight of AgBr = 0.12g
Weight of organic compound = 0.15g
A pale yellow precipitate soluble in ammonium hydroxide solution indicates the presence of:
The correct answer is option C
A pale yellow precipitate soluble in ammonium Hydroxide solution indicates the presence of Bromine.
In the test of nitrogen the Prussian blue color formed is of:
The correct answer is Option D.
In the Lassaigne's test for the detection of nitrogen in an organic compound, the appearance of a blue coloured compound is due to ferric ferrocyanide.
In this test, sodium fusion extract is boiled with ferrous sulphate and then acidified with conc. sulphuric acid. Prussian blue colour complex ferric ferrocyanide confirms the presence of nitrogen.
It is ferric ferrocyanide.