Organic Chemistry Some Basic Principles And Techniques Ques 67

67. Lassaigne’s test is used in qualitative analysis to detect

[1989]

(a) Nitrogen

(b) Sulphur

(c) Chlorine

(d) All of these

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Answer:

Correct Answer: 67.(d)

Solution:

  1. (d) Nitrogen, sulphur and halogens are tested in an organic compound by Lassaigne’s test.

The organic compound is fused with sodium metal as to convert these elements into ionisable inorganic substances,

$ \begin{aligned} & Na+C+N \longrightarrow NaCN \\ & 2 Na+S \longrightarrow Na_2 S \\ & 2 Na+X_2 \longrightarrow 2 NaX \end{aligned} $

The cyanide, sulphide or halide ions can be confirmed in aqueous solution by usual test.