Match the organic compounds in column - I with the Lassaigne's test results in column - II appropriately:…

Match the organic compounds in column - I with the Lassaigne's test results in column - II appropriately: \(\begin{array}{l} \begin{array}{|l|l|l|} \hline & \text { Column - I } & & \text { Column - II } \\ \hline \text { (A) } & \text { Aniline } & \text { (i) } & \text { Red color with } \mathrm{FeCl}_{3} \\ \hline \text { (B) } & \begin{array}{l} \text { Benzene sulfonic } \\ \text { acid } \end{array} & \text { (ii) } & \text { Violet color with sodium nitroprusside } \\ \hline \text { (C) } & \text { Thiourea } & \text { (iii) } & \mathrm{Blue} \text { color with hot and acidic solution of } \\ & & & \mathrm{FeSO}_{4} \end{array}\\ \hline\\ \end{array}\)
  1. \(\mathrm{A}-\) (ii); \(\mathrm{B}-\) (i); \(\mathrm{C}-\) (iii)
  2. \(\mathrm{A}-\) (iii); \(\mathrm{B}-\) (ii); \(\mathrm{C}-\) (i)
  3. \(\mathrm{A}-\) (ii); \(\mathrm{B}-\) (iii); \(\mathrm{C}-\) (i)
  4. \(\mathrm{A}-\) (iii); \(\mathrm{B}-\) (i); \(\mathrm{C}-\) (ii)

Solution

Lassaigne's test: In a qualitative analysis of organic compounds, a test for the detection of nitrogen, sulfur, and halogens present in organic compounds is Lassaigne's test. In this test, the organic compound and a small piece of Na metal are heated in a fusion tube. The basic principle of this test is that Na converts the elements in organic compound into ionic form (A) Aniline with Lassaigne's test: the aniline compound is boiled \(\mathrm{FeSO}_{4}\) with concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\), which will appear on Prussian blue color indicates the presence of nitrogen in the given organic compound. (B) benzene sulfonic acid with Lassaigne's test: the given compound treated with sodium nitroprusside gives the appearance of violet color indicates the sulfur present in the benzene sulfonic acid. (C) thiourea with Lassaigne's test: this compound on reacting with \(\mathrm{FeCl}_{3} / \mathrm{FeSO}_{4}\) will give blood-red color.

Asked in: JEE-TOPICTESTS-CHEMISTRY

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