Chemistry Q62 – JEE-MAIN 2025

Home Chemistry Basic ChemistryQuestion #68

Formation of

N a_{4} [F e (C N)_{5} N O S]

, a purple coloured complex formed by addition of sodium nitroprusside in sodium carbonate extract of salt indicates the presence of :

Clue 1 of 3: Qualitative Analysis

This question relates to a specific chemical test used to identify a particular anion in a salt solution.

🥷

Ninja Strategy•Specific Reagent Recall

Recognize that sodium nitroprusside is a highly specific reagent used to detect sulphide ions, making other options incorrect.

🧠 Full Solution Path

Step 1: Identify the Reagent and Product✦ Active

The question describes a test where sodium nitroprusside ( $N a_{2} [F e (C N)_{5} N O]$ ) is added to a sodium carbonate extract of a salt, resulting in the formation of a purple-colored complex, $N a_{4} [F e (C N)_{5} N O S]$ .

💡 Teacher's Secret Hint

Recognize sodium nitroprusside as a common reagent in qualitative analysis.

Step 2: Recall the Specific Test○ Expand

The formation of a purple complex with sodium nitroprusside is a characteristic test for the presence of sulphide ions ( $S^{2 -}$ ). The reaction is:

N a_{2} [F e (C N)_{5} N O] + S^{2 -} \to N a_{4} [F e (C N)_{5} N O S]

💡 Teacher's Secret Hint

Remember the specific color changes associated with common qualitative tests.

Step 3: Conclude the Presence of the Ion○ Expand

Since the purple complex $N a_{4} [F e (C N)_{5} N O S]$ is formed, it indicates the presence of sulphide ion.

💡 Teacher's Secret Hint

Ensure to distinguish between similar-sounding ions like sulphate, sulphite, and sulphide.

✦ STEM Console utilizes AI models to generate step-by-step explanations and math clues. AI can make mistakes.

Chemistry Question 62 – JEE-MAIN 2025

Clue 1 of 3: Qualitative Analysis

🧠 Full Solution Path