Question

Statement-I : Test for nitrite; sulphanilic acid and 1-napthylamine are used.
Statement-II : Acidified nitrite is di-azotized with sulphanilic acid and coupled with 1-napthylamine.
Select the correct statement.

• A. Both Statements are correct.
• B. Both Statements are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Hint:

This is a standard qualitative analysis spot test for $\text{NO}_2^-$. Formation of red azo dye confirms nitrite.

Answer 1

The Correct Option is A

Both statements provided in the question relate to the chemical test for the detection of nitrite ions using specific reagents. Let's evaluate each statement:

1. Statement-I: Test for nitrite; sulphanilic acid and 1-napthylamine are used.
   • This statement is correct. The test for nitrites involves the use of sulphanilic acid and 1-napthylamine. When nitrite is present, it reacts with sulphanilic acid to form a diazonium salt, which then couples with 1-napthylamine to produce a red-colored azo dye. This color change is indicative of the presence of nitrite ions.
2. Statement-II: Acidified nitrite is di-azotized with sulphanilic acid and coupled with 1-napthylamine.
   • This statement is also correct. The test is typically performed under acidic conditions, which helps favor the formation of a diazonium salt through the reaction of nitrite with sulphanilic acid. The resulting diazonium salt then couples with 1-napthylamine to form an azo compound, confirming the presence of nitrite ions through the development of a red color.

Based on the examination of both statements, we can conclude that both statements are correct, as they accurately describe the chemical process used in the test for nitrite ions.