Question

The CORRECT statement(s) about sodium nitroprusside is (are)

• A. It is a paramagnetic complex
• B. Nitroprusside ion is formed in the brown ring test for nitrates
• C. It is used for the detection of S$^{2-}$ in aqueous solution
• D. It contains nitrosyl ligand as NO$^+$

Hint:

Linear NO ligand → NO$^+$; Bent NO ligand → NO$^-$. Sodium nitroprusside gives a purple color with sulfide ions (qualitative test).

Answer 1

The Correct Option is C, D

Step 1: Structure and oxidation states.
Sodium nitroprusside = Na$_2$[Fe(CN)$_5$(NO)].
Here Fe is in +2 oxidation state and NO acts as a nitrosyl cation (NO$^+$).
Step 2: Properties.
- The complex is paramagnetic due to one unpaired electron.
- It is used for qualitative detection of S$^{2-}$ ions (formation of purple color due to [Fe(CN)$_5$(NOS)]$^{4-}$ complex).
- The nitrosyl group is linear, indicating NO$^+$ character.
Step 3: Conclusion.
Correct statements are (A), (C), and (D).