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 :

Question

Given below are the four isomeric compounds \(P, Q, R, S\):
\(P\): Aromatic compound containing an \(-\mathrm{OH}\) group
\(Q\): Aromatic compound containing an \(-\mathrm{CHO}\) group (aldehyde)
\(R\): Aromatic compound containing a ketone group
\(S\): Aromatic compound containing a ketone group Identify the correct statements from below:
[A.] \(Q, R\) and \(S\) will give precipitate with \(2,4\)-DNP.
[B.] \(P\) and \(Q\) will give positive Baeyer’s test.
[C.] \(Q\) and \(R\) will give sooty flame.
[D.] \(R\) and \(S\) will give yellow precipitate with \(I_2/\mathrm{NaOH}\).
[E.] \(Q\) alone will deposit silver with Tollens’ reagent. Choose the correct option.

Answer 1

Let's evaluate the given statements about the nickel(II) complex of dimethylglyoxime to determine their correctness:

The statement A. It is red in colour. is correct. The nickel(II) complex with dimethylglyoxime forms a red precipitate, which is a known characteristic of the Ni(dmg)₂ complex.
The statement B. It has a high solubility in water at pH = 9. is incorrect. The Ni(dmg)₂ complex is known to be relatively insoluble in water, particularly under neutral and basic conditions like pH = 9, where it forms a precipitate instead.
The statement C. The Ni ion has two unpaired d-electrons. is incorrect. In the nickel(II) complex with dimethylglyoxime, Ni²⁺ is in a square planar geometry. In this geometry, due to strong ligand field and electron pairing, the nickel ion typically has no unpaired electrons.
The statement D. The N – Ni – N bond angle is almost close to 90°. is correct. In a square planar geometry, the N – Ni – N angle is approximately 90°.
The statement E. The complex contains four five-membered metallacycles (metal containing rings). is incorrect. The complex actually consists of two five-membered metallacycles, not four.

Based on the evaluation:

Statement B is incorrect as the complex is insoluble in water at pH = 9.
Statement C is incorrect as the nickel ion does not have unpaired d-electrons in the complex.
Statement E is incorrect as the complex forms two, not four, five-membered metallacycles.

Thus, the incorrect statements are B, C, and E. The correct answer is B, C and E Only.

Answer 2

Let's evaluate the given statements about the nickel(II) complex of dimethylglyoxime to determine their correctness:

The statement A. It is red in colour. is correct. The nickel(II) complex with dimethylglyoxime forms a red precipitate, which is a known characteristic of the Ni(dmg)₂ complex.
The statement B. It has a high solubility in water at pH = 9. is incorrect. The Ni(dmg)₂ complex is known to be relatively insoluble in water, particularly under neutral and basic conditions like pH = 9, where it forms a precipitate instead.
The statement C. The Ni ion has two unpaired d-electrons. is incorrect. In the nickel(II) complex with dimethylglyoxime, Ni²⁺ is in a square planar geometry. In this geometry, due to strong ligand field and electron pairing, the nickel ion typically has no unpaired electrons.
The statement D. The N – Ni – N bond angle is almost close to 90°. is correct. In a square planar geometry, the N – Ni – N angle is approximately 90°.
The statement E. The complex contains four five-membered metallacycles (metal containing rings). is incorrect. The complex actually consists of two five-membered metallacycles, not four.

Based on the evaluation:

Statement B is incorrect as the complex is insoluble in water at pH = 9.
Statement C is incorrect as the nickel ion does not have unpaired d-electrons in the complex.
Statement E is incorrect as the complex forms two, not four, five-membered metallacycles.

Thus, the incorrect statements are B, C, and E. The correct answer is B, C and E Only.

Show Hint

The Correct Option is B

Solution and Explanation

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