The statements that are incorrect about the nickel(II) complex of dimethylglyoxime are : Choose the correct answer from the options given below :
- C and E Only
- A, D and B Only
- B, C and E Only
- C and D Only
Answer
(3) B, C and E Only
Solution
[Ni(dmg)2] is formed as a red precipitate when DMG is added to an ammoniacal Ni2+ solution.
A. Correct: it is a red (rosy-red) complex.
B. Incorrect: it is insoluble in water and precipitates in ammoniacal medium (pH ≈ 9); this is why it is used to detect and estimate nickel.
C. Incorrect: Ni2+ (3d8) with the strong-field dmg ligand is dsp2, square planar; all 8 d electrons are paired, so the complex is diamagnetic.
D. Correct: square planar geometry N–Ni–N angles close to 90 .
E. Incorrect: the two dmg ligands form only two five-membered chelate rings (Ni–N–C–C–N); the other two rings, closed by O–H···O hydrogen bonds, are six-membered.
Incorrect statements: B, C and E
Answer: (3)