Question

The compound that does not give a positive test for nitrogen in Lassaigne’s test is

• A.
• B.
• C.
• D.

Hint:

For Lassaigne’s test, nitrogen must be directly bonded to carbon in the organic com pound for a positive test.

Answer 1

The Correct Option is B

In Lassaigne’s test, compounds containing nitrogen form a characteristic blue or purple color with sodium fusion extract when treated with sodium picrate or other reagents. The compound that does not give a positive test for nitrogen is the one that does not contain nitrogen in its structure.

The given compounds are:

• (A) Nitro phenol (C₆H₄NO₂OH) contains nitrogen and will give a positive test.
• (B) Chlorobenzene (C₆H₅Cl) does not contain nitrogen, and thus does not give a positive test for nitrogen in Lassaigne’s test.
• (C) Aniline (C₆H₄NH₂) contains nitrogen and will give a positive test.
• (D) Aminobenzene (C₆H₄NH₂) contains nitrogen and will give a positive test.

Thus, the compound that does not give a positive test for nitrogen is (B) Chlorobenzene.