Class 11Chemistry8-3.Organic Chemistry : Purification and characterizationChemical analysis of organic compounds
MediumGive the answers for the Lassaigne test:
$(i)$ If nitrogen and sulphur are both present,what observation is observed?
$(ii)$ If bromine is present,what is the observation?
$(iii)$ In the Lassaigne extract,if black precipitates are not obtained upon adding $CH_3COOH$ and lead acetate,what does this indicate?
$(iv)$ What is the reason for adding $FeSO_4$ to the Lassaigne extract?
$(v)$ Why is the Prussian blue colour observed?
$(vi)$ What does the violet colour with sodium nitroprusside in the Lassaigne extract indicate?
$(i)$ If nitrogen and sulphur are both present,what observation is observed?
$(ii)$ If bromine is present,what is the observation?
$(iii)$ In the Lassaigne extract,if black precipitates are not obtained upon adding $CH_3COOH$ and lead acetate,what does this indicate?
$(iv)$ What is the reason for adding $FeSO_4$ to the Lassaigne extract?
$(v)$ Why is the Prussian blue colour observed?
$(vi)$ What does the violet colour with sodium nitroprusside in the Lassaigne extract indicate?
(N/A) $(i)$ $A$ blood-red colour is obtained due to the formation of $[Fe(SCN)]^{2+}$.
$(ii)$ By adding $AgNO_3$,a pale yellow precipitate of $AgBr$ is formed.
$(iii)$ It indicates that sulphur is absent in the organic compound.
$(iv)$ $FeSO_4$ is added to react with $CN^-$ ions to form ferrocyanide ions,which then react with $Fe^{3+}$ ions.
$(v)$ It is due to the formation of ferric ferrocyanide,$Fe_4[Fe(CN)_6]_3$.
$(vi)$ It indicates that sulphur is present in the compound,forming $Na_4[Fe(CN)_5NOS]$.
$(ii)$ By adding $AgNO_3$,a pale yellow precipitate of $AgBr$ is formed.
$(iii)$ It indicates that sulphur is absent in the organic compound.
$(iv)$ $FeSO_4$ is added to react with $CN^-$ ions to form ferrocyanide ions,which then react with $Fe^{3+}$ ions.
$(v)$ It is due to the formation of ferric ferrocyanide,$Fe_4[Fe(CN)_6]_3$.
$(vi)$ It indicates that sulphur is present in the compound,forming $Na_4[Fe(CN)_5NOS]$.
Explore More
Similar Questions
If on adding $FeCl_3$ solution to acidified Lassaigne solution of an organic compound a blood red colouration is produced,it indicates the presence of
Medium
View SolutionIn the test for halogens,why is nitric acid added to the sodium fusion extract before adding silver nitrate?
Easy
View SolutionWhich compound is formed as a violet-colored complex during the test for sulfur?
Easy
View SolutionWhich one of the following sets of elements can be detected using sodium fusion extract?
How is the silver halide obtained from an organic compound distinguished?
Easy
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo