Question

Match List-I with List-II

Choose the correct answer from the options given below :

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

Hint:

Remember that primary valency is the oxidation state and secondary valency is the coordination number. For polydentate ligands, multiply the denticity by the number of ligands to calculate their contribution to the secondary valency.

Answer 1

The Correct Option is B

To correctly match List-I with List-II, determine the primary and secondary valencies for each complex in List-I. Primary valency is the central metal atom's oxidation state; secondary valency is the coordination number, representing the count of ligand atoms bonded to the central metal atom.

1. (A) \([Co(en)_2Cl_2]Cl\):
   • Primary Valency: Co's oxidation state is +3.
   • Secondary Valency: Two bidentate ethylenediamine (en) ligands provide four coordination sites. Two chloride ligands bond to cobalt, yielding a coordination number of 6.
2. (B) \([Pt(NH_3)_2Cl(NO_2)]\):
   • Primary Valency: Pt's oxidation state is +4.
   • Secondary Valency: The coordination number is 4, with NH₃, Cl, and NO₂ as ligands.
3. (C) \(Hg[Co(SCN)_4]\):
   • Primary Valency: Hg's oxidation state is +2.
   • Secondary Valency: Four SCN ligands result in a coordination number of 4.
4. (D) \([Mg(EDTA)]^{2-}\):
   • Primary Valency: Mg's oxidation state is +2.
   • Secondary Valency: EDTA is a hexadentate ligand; it uses four coordination sites here, yielding a coordination number of 4.

The correct matching based on this analysis is:

• (A) - (I): Primary Valency 3, Secondary Valency 6
• (B) - (IV): Primary Valency 4, Secondary Valency 4
• (C) - (II): Primary Valency 2, Secondary Valency 4
• (D) - (III): Primary Valency 2, Secondary Valency 4

The correct answer is: (A)-(I), (B)-(IV), (C)-(II), (D)-(III).