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In Lassaigne's extract of an organic compound, both nitrogen and sulphur are present, which gives blood red colour with Fe3+ due to the formation of-
(3) [Fe(SCN)]2+
When N and S are both present, sodium thiocyanate is formed during fusion:
Na + C + N + S NaSCN
It gives a blood red colour with Fe3+:
Fe3+ + SCN- [Fe(SCN)]2+ (blood red)
Answer: (3)
The Kjeldahl's method for the estimation of nitrogen can be used to estimate the amount of nitrogen in which one of the following compounds?
Paper chromatography is an example of :
The most suitable method of separation of 1 : 1 mixture of ortho and para-nitrophenols is
In Dumas method for estimation of nitrogen, 0.25 g of an organic compound gave 40 mL of nitrogen collected at 300 K temperature and 725 mm pressure. If the aqueous tension at 300 K is 25 mm, the percentage of nitrogen in the compound is
In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75 g of sample neutralized 10 mL of 1 M H2SO4. The percentage of nitrogen in the soil is
Nitrogen detection in an organic compound is carried out by Lassaigne's test. The blue colour formed corresponds to which of the following formulae?
The Lassaigne's extract is boiled with conc. HNO3 while testing for halogens. By doing so it
In Dumas method of estimation of nitrogen, 0.35 g of an organic compound gave 55 mL of nitrogen collected at 300 K temperature and 715 mm pressure. The percentage composition of nitrogen in the compound would be (aqueous tension at 300 K = 15 mm).
The best method for the separation of naphthalene and benzoic acid from their mixture is
Which of the following is incorrect?