Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.

(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

The correct answer is option 4. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i).

Let us delve deeper into the properties of each ligand and why they match with their corresponding entries in Column II:

(a) NH₃(iv) Monodentate ligand: Ammonia is a Monodentate ligand. Ammonia \((NH_3)\) can donate one pair of electrons from its nitrogen atom to form one coordinate bond with a central metal ion. It does not form a ring structure.

(b) NO₂(iii) Ambidentate ligand: \(NO_2\) is an ambidentate ligand. The nitrite ion \((NO_2^-)\)can donate electrons either from the nitrogen atom (as nitro-N) or from one of the oxygen atoms (as nitro-O), but not simultaneously from both. It cannot form a ring structure.

(c) en(ii) Bidentate ligand: Ethylene diamine (en) bidentate ligand. Ethylenediamine (en) has two amine groups \((-NH_2)\) that can each donate a pair of electrons to form two coordinate bonds with a central metal ion. It typically forms a ring structure when coordinated.

(d) EDTA(i) Chelating ligand: EDTA is a chelating ligand. EDTA is a large organic molecule with four carboxylate groups \((-COO^-)\) and two amine groups \((-NH_2)\). It can donate multiple pairs of electrons to form multiple coordinate bonds with a central metal ion, forming a stable ring structure.

Therefore, the correct matching is: (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

This pairing correctly identifies each ligand in Column I with its corresponding coordination type in Column II based on their chemical properties and coordination behaviors in coordination chemistry.