Question

Match the Column-I (Ligands) with Column-II (Ligand type):
Column-I: (I) \(NO_{2}^{-}\), (II) \(OH^{-}\), (III) \(C_{2}O_{4}^{2-}\), (IV) EDTA.
Column-II: (A) Hexadentate, (B) Bidentate, (C) Monodentate, (D) Ambidentate.

• A. I-D, II-C, III-B, IV-A
• B. I-C, II-D, III-B, IV-A
• C. I-C, II-D, III-A, IV-B
• D. I-A, II-C, III-B, IV-D

Hint:

Remember these important ligands: \[ \boxed{ \begin{aligned} OH^- &\rightarrow \text{Monodentate}\\ H_2O &\rightarrow \text{Monodentate}\\ NH_3 &\rightarrow \text{Monodentate}\\ NO_2^- &\rightarrow \text{Ambidentate}\\ SCN^- &\rightarrow \text{Ambidentate}\\ C_2O_4^{2-} &\rightarrow \text{Bidentate}\\ EDTA &\rightarrow \text{Hexadentate} \end{aligned} } \] These ligands are frequently asked in competitive examinations.

Answer 1

The Correct Option is A

Concept: Ligands are ions or molecules that donate one or more lone pairs of electrons to a central metal atom or ion to form coordinate bonds. Depending upon the number of donor atoms, ligands are classified as:

• Monodentate ligand – donates one lone pair.

• Bidentate ligand – donates two lone pairs.

• Hexadentate ligand – donates six lone pairs.

• Ambidentate ligand – has two different donor atoms but can coordinate through only one at a time.

Step 1: Identify the type of each ligand.
\[ NO_2^- \] can coordinate through nitrogen or oxygen atoms. Hence, \[ \boxed{NO_2^- \rightarrow \text{Ambidentate}.} \] \[ OH^- \] has only one donor atom (oxygen). Hence, \[ \boxed{OH^- \rightarrow \text{Monodentate}.} \] \[ C_2O_4^{2-} \] (oxalate ion) coordinates through two oxygen atoms. Hence, \[ \boxed{C_2O_4^{2-}\rightarrow \text{Bidentate}.} \] EDTA possesses six donor atoms. Hence, \[ \boxed{EDTA\rightarrow \text{Hexadentate}.} \]

Step 2: Match the columns.
Therefore, \[ \begin{aligned} I &\rightarrow D,\\ II &\rightarrow C,\\ III &\rightarrow B,\\ IV &\rightarrow A. \end{aligned} \] This matches \[ \boxed{\textbf{Option (A)}}. \]