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
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
NaSCN
[Fe(CN)5 NOS]4-
[Fe(SCN)]2+
Fe4[Fe(CN6)]3.xH2O
The Correct Option is C
Approach Solution - 1
The given question discusses the identification test involving Lassaigne's extract, which is utilized to detect the presence of nitrogen and sulfur in organic compounds. When both elements are present, a specific colored reaction occurs.
The Lassaigne’s extract is first reacted to form sodium thiocyanate (NaSCN). In the presence of ferric ions (Fe3+), NaSCN forms a complex with the ferric ions. The specific complex responsible for the blood red coloration is the thiocyanatoiron complex, given by the chemical formula [Fe(SCN)]2+.
This complex occurs because the thiocyanate ion (SCN-) acts as a ligand, binding to the ferric ion to form the colored complex. The reaction can be summarised as:
Thus, the correct answer, based on the given options, is:
[Fe(SCN)]2+
Approach Solution -2
When both nitrogen and sulfur are present in an organic compound, sodium thiocyanate is produced. This combination does not produce prussian blue because there are no free cyanide lons. Instead, it produces a blood-red color.
Na + C + N + S \(\to\) NaSCN
Fe+3 + SCN \(\to\) [Fe(SCN)]2+(Red blood)
Therefore, The correct option is (C): [Fe(SCN)]2+(Red Blood)
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Concepts Used:
Introduction to Organic Chemistry
Organic chemistry is the branch of chemistry that involves the scientific study of organic compounds. Organic chemistry primarily deals with the structure and chemical composition of organic compounds, the physical and chemical properties of organic compounds, and the chemical reactions undergone by these compounds.
Reaction Intermediates in Organic Chemistry:
Intermediates can be understood as the first product of a consecutive reaction. For example, in a chemical reaction, if A→B and B→C, then, B can be said to be the intermediate for reaction A→C. The reactions in organic chemistry occur via the formation of these intermediates.
Reagents in Organic Chemistry:
Reagents are the chemicals that we add to bring about a specific change to an organic molecule. Any general reaction in organic chemistry can be written as:
Substrate + Reagent → Product
Where the substrate is an organic molecule to which we add the reagent. Based on the ability to either donate or abstract electrons, the reagents can be classified as:
- Electrophiles
- Nucleophiles