Question

Which of the following does not give LASSAIGNE'S TEST :- (a)Hydoxylamine Hydrochloride ..... (b) Nitromethane......(c)propane nitrile .... (d)ethaneamine.

Answer 1

Lassaigne's test is used to detect the presence of elements: Nitrogen (N), Sulfur(S), Chlorine (Cl), Bromine(Br) and Iodine (I). This test involves following two steps:

I. preparation of sodium fusion extract (SFE).

II. detection of element using SFE

SUMMARY SHEET OF LASSAIGNE'S TEST

If you have:

a) Hydroxylamine Hydrochloride (NH₂OH*HCl) [Cl and N can be detected]

b) Nitromethane CH₃NO₂ [N can be detected, but*...]

c) propane nitrile C₂H₅CN [N can be detected]

d) ethaneamine C₂H₅NH₂ [N can be detected]

*But process for b is very slow, so it can't give Lassaigne's test.