JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Practical and Analytical Chemistry

Which of the following nitrogen containing compound does not give Lassaigne's test?

(A)Phenyl hydrazine
(B)Glycene
(C)Urea
(D)Hydrazine✓ Correct

Answer: (D)

Solution

Lassaigne's (sodium fusion) test detects N, S and halogens by first converting them, together with the carbon of the compound, into ionic species (

NaCN

, etc.). It therefore requires carbon in the molecule.

Hydrazine,

H_{2} N - N H_{2}

, contains no carbon, so it cannot form

NaCN

and gives no Lassaigne's test. Option D.

JEE Main · 2024 · 04 Apr 2024 · Shift 1 · Single correct option

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