In each of the following questions, a Statement-I is given followed by corresponding Statement-II just below. Mark the correct answer as indicated.

Statement-I: Lassaigne’s test is not shown by diazonium compounds.

Statement-II: Diazonium compounds lose \(N_2\) on heating before they combine with fused sodium.

If both Statement-I and Statement- II are true and reason is the correct explanation of assertion.

The correct answer is option 1. If both Statement-I and Statement- II are true and reason is the correct explanation of assertion.

Let us delve into the explanations for both Statement-I and Statement-II and why option 1 is correct:

Statement-I: Lassaigne’s test is not shown by diazonium compounds.

Lassaigne's test is a classical chemical test used to detect the presence of nitrogen and sulfur in organic compounds. In Lassaigne's test, the organic compound is heated strongly with sodium metal. This process leads to the formation of sodium cyanide \((NaCN)\) and sodium sulfide \((Na_2S)\) if nitrogen and sulfur are present in the organic compound, respectively. Diazonium compounds, which contain the \(-N_2^+\) group (diazonium group), do not give positive results in Lassaigne's test. Diazonium compounds are unstable and readily decompose upon heating to release nitrogen gas (\(N_2\)). Therefore, they do not undergo the necessary reactions with sodium to form sodium cyanide or sodium sulfide, which are the detectable products in Lassaigne's test. Hence, diazonium compounds do not show Lassaigne's test because they do not yield the expected products upon heating with sodium.

Statement-II: Diazonium compounds lose \(N_2\) on heating before they combine with fused sodium.

Diazonium compounds are unstable and decompose readily when heated to liberate nitrogen gas (\(N_2\)). This decomposition occurs before any reaction with fused sodium metal can take place. When diazonium compounds are heated, they undergo a decomposition reaction where the \(-N_2^+\) group leaves as nitrogen gas. This happens before the diazonium compound can react with sodium metal to form sodium cyanide or sodium sulfide. Therefore, the liberation of \(N_2\) gas occurs prior to any interaction with sodium metal during Lassaigne's test.

Thus the correct answer is option 1: If both Statement-I and Statement-II are true and Statement-II provides a correct explanation for Statement-I.

This option correctly identifies that both statements are factually accurate:

Statement-I: Diazonium compounds do not show Lassaigne's test because they decompose to release nitrogen gas instead of forming the detectable products.

Statement-II: Diazonium compounds indeed lose \(N_2\) on heating before they can react with sodium to form sodium cyanide or sodium sulfide.

Furthermore, Statement-II provides a valid explanation (reason) for Statement-I, clarifying why diazonium compounds do not exhibit Lassaigne's test.

Therefore, option 1 is the correct answer as it accurately reflects the relationship between the statements and their explanations regarding diazonium compounds and Lassaigne's test.