Question

Given below are two statements: Statement I: Griess–Ilosvay test is used for the detection of nitrite ion, which involves the use of sulphanilic acid and \(\alpha\)-naphthylamine reagent. Statement II: In the above test, sulphanilic acid is diazotized by the acidified nitrite ion, which on further coupling with \(\alpha\)-naphthylamine forms an azo-dye. In the light of the above statements, choose the correct answer from the options given below.

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are true
• C. Both Statement I and Statement II are false
• D. Statement I is true but Statement II is false

Hint:

Most nitrite detection tests involve diazotization reactions followed by azo-coupling, producing intensely colored dyes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The Griss-Ilosvay test is a sensitive chemical test used for the qualitative detection and quantitative estimation of nitrite (\(NO_2^-\)) ions in various samples like water or biological fluids.
Step 2: Detailed Explanation:
In Statement I: The test indeed utilizes a combination of sulphanilic acid and \(\alpha\)-naphthylamine (1-naphthylamine) in an acidic medium (usually acetic acid).
In Statement II: The reaction mechanism involves two stages:
1. Diazotization: Nitrite ions react with sulphanilic acid in the presence of an acid to form a diazonium salt.
\[ \text{Sulphanilic acid} + NO_2^- + H^+ \rightarrow \text{Diazonium salt} + 2H_2O \]
2. Coupling: The resulting diazonium salt then couples with \(\alpha\)-naphthylamine to form a red-colored azo dye.
\[ \text{Diazonium salt} + \alpha\text{-naphthylamine} \rightarrow \text{Red Azo-dye} \]
Since both the reagent components and the reaction pathway described are scientifically accurate, both statements are true.
Step 3: Final Answer:
Both Statement I and Statement II are true.