Question

The statements that are incorrect about the nickel(II) complex of dimethylglyoxime are :
A. It is red in colour.
B. It has a high solubility in water at pH = 9.
C. The Ni ion has two unpaired d-electrons.
D. The N – Ni – N bond angle is almost close to 90°.
E. The complex contains four five-membered metallacycles (metal containing rings).
Choose the correct answer from the options given below :

• A. C and E Only
• B. B, C and E Only
• C. A, D and B Only
• D. C and D Only

Hint:

Remember: "Red-Dead-Square." Red color, insoluble (Dead), and Square planar.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
$Ni(DMG)_2$ is a square planar, neutral complex. Its stability and distinct color are due to its unique structure involving intramolecular hydrogen bonding.
Step 2: Detailed Explanation:
- Statement A: Correct. The complex is a rosy-red precipitate. - Statement B: Incorrect. It is highly insoluble in water, which is why it's used for the gravimetric estimation of Nickel. - Statement C: Incorrect. As a square planar $d^8$ complex with strong field behavior (from $N$ donors), it is diamagnetic (0 unpaired electrons). - Statement D: Correct. Square planar geometry implies angles close to 90°. - Statement E: Incorrect. It contains two five-membered chelate rings (Ni-N-C-C-N) and two six-membered rings formed by hydrogen bonding (O-H...O).
Step 3: Final Answer:
The incorrect statements are B, C, and E.