ChemistryHardHigh School (11–12)Organic Chemistry: Some Basic Principles and Techniques › Purification and Analysis of Organic CompoundsNEET
Created by StemPy LabAssertion (A): A student fuses hydrazine, , with sodium, as in Lassaigne's test, and boils the extract with iron(II) sulphate and then acid. Although hydrazine contains nitrogen, no Prussian blue colour appears. Reason (R): In the fusion, nitrogen is changed to sodium cyanide only together with carbon from the compound: .
← All Quizzes
← The figure shows tests on a sodium fusion extract and what was seen. Read these conclusions.
(i) Tube 1 shows nitrogen; the blue colour is iron(III) hexacyanidoferrate(II).
(ii) The violet colour in Tube 4 comes from thiocyanate ions.
(iii) Tube 3 shows chlorine; bromine would give a pale yellow precipitate.
(iv) Nitric acid in Tube 3 removes cyanide and sulphide, which would also react with silver nitrate.
(v) With sulphur present, the Prussian blue shows that too little sodium was used.
How many of the statements above are correct?In Carius method, 0.294 g of an organic compound is heated with fuming nitric acid and silver nitrate, and gives 0.574 g of silver chloride, which is filtered, washed, dried and weighed. Each molecule of the compound has two chlorine atoms. Atomic masses in g mol⁻¹: Cl 35.5, Ag 108. What is the molar mass of the compound? →
Discussion (0)
Log in to join the discussion.
Loading…