Question

[Ni(H\(_2\)O)\(_4\)]\(^{2+}\) on reaction with ethane-1,2-diamine forms violet color complex. Its formula and magnetic property respectively are

• A. [Ni(H\(_2\)O)\(_4\)(en)\(_2\)]\(^{2+}\), Paramagnetic nature
• B. [Ni(H\(_2\)O)\(_2\)(en)\(_2\)]\(^{2+}\), Diamagnetic nature
• C. [Ni(en)\(_3\)]\(^{2+}\), Paramagnetic nature
• D. [Ni(H\(_2\)O)\(_2\)(en)\(_2\)]\(^{2+}\), Paramagnetic nature

Hint:

Coordination complexes can show varied colors and magnetic properties depending on the metal ion and ligands involved, influencing their electronic structure and properties.

Answer 1

The Correct Option is C

Determine the formula and properties of the complex.

When Ni\(^{2+}\) is complexed with ethane-1,2-diamine (en), it typically forms a coordination complex where ethane-1,2-diamine acts as a bidentate ligand, replacing water molecules. The complete replacement of water by three en ligands forms [Ni(en)\(_3\)]\(^{2+}\), which is known for its violet color and paramagnetic properties due to unpaired electrons in the d-orbital of Ni\(^{2+}\).

Conclusion: The correct formula and properties are given by option (3) [Ni(en)\(_3\)]\(^{2+}\), confirming it as paramagnetic.

Answer 2

To solve the problem, we need to identify the formula and magnetic property of the violet-colored complex formed by the reaction of \( \text{[Ni(H}_2\text{O})_6]^{2+} \) with ethane-1,2-diamine.

1. Understanding the Problem:
In this problem, the reaction involves a nickel complex with water molecules and ethane-1,2-diamine (a bidentate ligand). The result is a complex that exhibits a violet color. We need to determine its formula and magnetic properties.

2. Formula of the Complex:
The reaction involves the substitution of water molecules with ethane-1,2-diamine molecules. The formula for the resulting complex is \( \text{[Ni(H}_2\text{O})_4 \, \text{en}]^{2+} \), where "en" represents ethane-1,2-diamine.

3. Magnetic Properties:
Nickel(II) in this complex is a d^8 metal ion. In the case of \( \text{[Ni(H}_2\text{O})_4 \, \text{en}]^{2+} \), the presence of unpaired electrons gives rise to paramagnetic behavior, meaning the complex will exhibit a magnetic moment. This is because there are unpaired electrons in the \( 3d \) orbitals of \( \text{Ni}^{2+} \).

4. Final Answer:
The correct formula for the complex is \( \text{[Ni(H}_2\text{O})_4 \, \text{en}]^{2+} \), and its magnetic property is paramagnetic.

Final Answer:
The correct option is (C) \( \text{[Ni(H}_2\text{O})_4 \, \text{en}]^{2+} \), Paramagnetic nature.