Which does not show lassiagne's test for nitrogen?(a)urea(b)hydrazine(c)phenylhydrazine(d)azobenzene?

Question

Answer

This is further used in the test for nitrogen. Hydrazine (H2N−NH2) do not contain carbon. It cannot form NaCN on fusion with sodium. Hence, hydrazine cannot give Lassaigne's test for nitrogen..
correct option is B

Answer

Hydrazine (NH2-NH2) does not give lassaigne test as it does not contain carbon. Urea,phenylhydrazine and azobenzene contains carbon and therefore can give lassaigne test.

Answer

Answer:

The Lassaigne's test for nitrogen is a chemical test used to detect the presence of nitrogen in organic compounds. It involves the formation of sodium cyanide (NaCN) by fusing the organic compound with sodium metal, followed by the reaction of NaCN with ferric chloride (FeCl3) to form a deep blue coloration, known as Prussian blue.

Among the given options, azobenzene does not show Lassaigne's test for nitrogen.

Reason:

Azobenzene is an organic compound with the molecular formula C12H10N2. It contains two nitrogen atoms in its structure, which could potentially react with sodium metal during the fusion step of Lassaigne's test. However, azobenzene does not undergo the Lassaigne's test due to the absence of active hydrogen atoms.

In the Lassaigne's test, the organic compound is fused with sodium metal, which converts nitrogen into sodium cyanide (NaCN). This conversion occurs through the formation of sodium amide (NaNH2), which is an intermediate compound. Sodium amide is formed by the reaction of sodium metal with active hydrogen atoms present in the organic compound.

Azobenzene lacks active hydrogen atoms in its structure, which are necessary for the formation of sodium amide. Therefore, during the fusion step, azobenzene does not react with sodium metal to produce NaCN. As a result, azobenzene does not show the characteristic deep blue coloration when treated with ferric chloride, indicating the absence of nitrogen in this compound.

Summary:

Among the given options, azobenzene does not show Lassaigne's test for nitrogen. This is because azobenzene lacks active hydrogen atoms necessary for the formation of sodium amide during the fusion step of Lassaigne's test. Without the formation of sodium amide, azobenzene does not react with ferric chloride to form the characteristic deep blue coloration, indicating the absence of nitrogen in this compound.

Similar NEET Doubts

Which of the following compounds to does not show Lassaigne's test for nitrogen?

Which of the following compounds to does not show Lassaignes test for nitrogen?

Which of the following compounds to does not show Lassaigne's test for nitrogen?

Identify the element that cannot be detected by Lassaigne’s test.

Why does nitrogen show anomalous properties with respect to other elements in group 15? A. Nitrogen has low ionization enthalpy B. Nitrogen atomhas high inter-electronic repulsions C. Nitrogen molecule bears a triple bond D. Absence of vacant d-orbitals?

Top Courses for NEETView all

Biology Class 11

Daily Test for NEET Preparation

NEET Mock Test Series 2025

Topic-wise MCQ Tests for NEET

Physics Class 11

Top Courses for NEET

Top Courses for NEET

Suggested Free Tests

Related Content

About NEET

NEET Preparation Material

How to Prepare for NEET Exam?

NCERT Based Study Material

NEET Mock Tests

Other Popular Exams

Company