Answer
Verified
405k+ views
Hint: Lassaigne’s extract is prepared to convert the covalent compound into ionic form. This is done by fusing the organic compound with sodium metal. Carbon elements should also be present in the organic compound for giving sodium cyanide to test the presence of nitrogen.
Complete step by step solution:
Lassaigne’s test is the general test for the detection of halogens, nitrogen and sulphur in an organic compound. In order to detect them, these have to be converted into their ionic forms.
Test for Nitrogen-
The presence of nitrogen in the organic compound is detected by fusing organic compounds with sodium metal to give sodium cyanide (NaCN) soluble in water. This is converted into sodium ferrocyanide by the addition of sufficient quantities of ferrous sulphate. Ferric ions generated during the process react with ferrocyanide to form Prussian blue precipitate of ferric ferrocyanide.
$\text{Na+C+N}\to \text{NaCN}$
$\text{6NaCN+ FeS}{{\text{O}}_{4}}\to \text{N}{{\text{a}}_{4}}[\text{Fe(CN}{{\text{)}}_{6}}]+\text{N}{{\text{a}}_{2}}\text{S}{{\text{O}}_{4}}$
$\text{N}{{\text{a}}_{4}}[\text{Fe(CN}{{\text{)}}_{6}}]+\text{F}{{\text{e}}^{3+}}\to \text{F}{{\text{e}}_{4}}{{[\text{Fe(CN}{{\text{)}}_{6}}]}_{3}}$
From the above discussion, we saw that there is a presence of carbon atoms in the organic compound and there is a formation of a complex of cyanide ions as a ligand. Therefore, the compound which does not have carbon atoms in it, will surely fail the nitrogen test done by Lassaigne’s extract.
Therefore, the correct option is (c) $\text{N}{{\text{H}}_{2}}\text{N}{{\text{H}}_{2}}$.
Note: We should also know that when nitrogen and sulphur both are present in an organic compound, sodium fusion will convert it into sodium thiocyanate which then reacts with $\text{F}{{\text{e}}^{3+}}$ to form blood colour complex${{[\text{Fe(SCN) }\!\!]\!\!\text{ }}^{2+}}$.
Complete step by step solution:
Lassaigne’s test is the general test for the detection of halogens, nitrogen and sulphur in an organic compound. In order to detect them, these have to be converted into their ionic forms.
Test for Nitrogen-
The presence of nitrogen in the organic compound is detected by fusing organic compounds with sodium metal to give sodium cyanide (NaCN) soluble in water. This is converted into sodium ferrocyanide by the addition of sufficient quantities of ferrous sulphate. Ferric ions generated during the process react with ferrocyanide to form Prussian blue precipitate of ferric ferrocyanide.
$\text{Na+C+N}\to \text{NaCN}$
$\text{6NaCN+ FeS}{{\text{O}}_{4}}\to \text{N}{{\text{a}}_{4}}[\text{Fe(CN}{{\text{)}}_{6}}]+\text{N}{{\text{a}}_{2}}\text{S}{{\text{O}}_{4}}$
$\text{N}{{\text{a}}_{4}}[\text{Fe(CN}{{\text{)}}_{6}}]+\text{F}{{\text{e}}^{3+}}\to \text{F}{{\text{e}}_{4}}{{[\text{Fe(CN}{{\text{)}}_{6}}]}_{3}}$
From the above discussion, we saw that there is a presence of carbon atoms in the organic compound and there is a formation of a complex of cyanide ions as a ligand. Therefore, the compound which does not have carbon atoms in it, will surely fail the nitrogen test done by Lassaigne’s extract.
Therefore, the correct option is (c) $\text{N}{{\text{H}}_{2}}\text{N}{{\text{H}}_{2}}$.
Note: We should also know that when nitrogen and sulphur both are present in an organic compound, sodium fusion will convert it into sodium thiocyanate which then reacts with $\text{F}{{\text{e}}^{3+}}$ to form blood colour complex${{[\text{Fe(SCN) }\!\!]\!\!\text{ }}^{2+}}$.
Recently Updated Pages
Basicity of sulphurous acid and sulphuric acid are
Three beakers labelled as A B and C each containing 25 mL of water were taken A small amount of NaOH anhydrous CuSO4 and NaCl were added to the beakers A B and C respectively It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas in case of beaker C the temperature of the solution falls Which one of the following statements isarecorrect i In beakers A and B exothermic process has occurred ii In beakers A and B endothermic process has occurred iii In beaker C exothermic process has occurred iv In beaker C endothermic process has occurred
What is the stopping potential when the metal with class 12 physics JEE_Main
The momentum of a photon is 2 times 10 16gm cmsec Its class 12 physics JEE_Main
How do you arrange NH4 + BF3 H2O C2H2 in increasing class 11 chemistry CBSE
Is H mCT and q mCT the same thing If so which is more class 11 chemistry CBSE
Trending doubts
Difference Between Plant Cell and Animal Cell
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
Summary of the poem Where the Mind is Without Fear class 8 english CBSE
Give 10 examples for herbs , shrubs , climbers , creepers
Write an application to the principal requesting five class 10 english CBSE
What organs are located on the left side of your body class 11 biology CBSE
What is the z value for a 90 95 and 99 percent confidence class 11 maths CBSE