Question

Identify neutral complex from following.

• A. Tetracyanonickelate (II) ion
• B. Sodiumhexafluoroaluminate (III)
• C. Triamminetrinitrocobalt (III)
• D. Tetraamminecopper (II) ion

Hint:

Neutral complexes do not have ionizable counter-ions outside the brackets.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
A neutral complex is a coordination compound that has no net charge on the complex sphere and is not paired with counter ions.

Step 3: Detailed Explanation:
- (A) Tetracyanonickelate (II) ion: $[\text{Ni}(\text{CN})_4]^{2-}$. It is an anionic complex.
- (B) Sodium hexafluoroaluminate (III):
$\text{Na}_3[\text{AlF}_6]$. This contains counter ions ($\text{Na}^+$). The complex ion itself is anionic ($[\text{AlF}_6]^{3-}$).
- (C) Triamminetrinitrocobalt (III): $[\text{Co}(\text{NH}_3)_3(\text{NO}_2)_3]$.
- Oxidation state of Co $= +3$.
- Charge of 3 $\text{NH}_3$ (neutral) $= 0$.
- Charge of 3 $\text{NO}_2$ (anionic) $= -3$.
- Net charge $= (+3) + 0 + (-3) = 0$. This is a neutral molecule.
- (D) Tetraamminecopper (II) ion: $[\text{Cu}(\text{NH}_3)_4]^{2+}$. It is a cationic complex.

Step 4: Final Answer:
Option C is a neutral complex.