Match List - I with List - II. List – I List – II (A) Tetracarbonylni…

The correct answer is Option 2. (A)-(IV), (B)-(III), (C)-(II), (D)-(I)

List – I	List – II
(A) Tetracarbonylnickel(0)	(IV) $[Ni(CO)_4]$
(B) Tetraammineaquachloridocobalt(III) chloride	(III) $[Co(NH_3)_4(H_2O)Cl]Cl_2$
(C) Potassium tetrahydroxidozincate (II)	(II) $K_2[Zn(OH)_4]$
(D) Dichloridobis(ethane-1,2-diamine)cobalt(III)	(I) $[CoCl_2(en)_2]^+$

Let us break down each compound from List – I and match it to the correct complex from List – II with detailed explanations

(A) Tetracarbonylnickel(0) : (IV) $[Ni(CO)_4]$

Tetracarbonylnickel(0) is a coordination complex where nickel is in the zero oxidation state, and it is coordinated with four carbon monoxide \((CO)\) ligands. The formula of this complex is \([Ni(CO)_4]\). The carbon monoxide ligands are neutral and coordinate to the nickel atom through their carbon atoms.

(B) Tetraammineaquachloridocobalt(III) chloride : (III) $[Co(NH_3)_4(H_2O)Cl]Cl_2$

This complex contains cobalt in the +3 oxidation state and is coordinated by four ammonia \((NH_3)\) ligands, one water \((H_2O)\) ligand, and one chloride \((Cl)\) ligand. The chloride outside the coordination sphere is counteracting the positive charge of the complex. The formula is \([Co(NH_3)_4(H_2O)Cl]Cl_2\), where the chloride ion outside the square brackets represents the counterion to balance the charge.

(C) Potassium tetrahydroxidozincate(II) : (II) $K_2[Zn(OH)_4]$

In this complex, zinc is in the +2 oxidation state and is surrounded by four hydroxide \((OH^-)\) ions. Potassium \((K^+)\) is present as a counterion to balance the negative charge of the tetrahydroxidozincate(II) anion. The formula for this complex is \(K_2[Zn(OH)_4]\), where the two potassium ions balance the -2 charge of the anion \([Zn(OH)_4]^{2-}\).

(D) Dichloridobis(ethane-1,2-diamine)cobalt(III):(I) $[CoCl_2(en)_2]^+$

This complex contains cobalt in the +3 oxidation state and is coordinated by two ethane-1,2-diamine (en) ligands and two chloride \((Cl^-)\) ions. The ethane-1,2-diamine is a bidentate ligand, meaning each ligand can form two bonds with the metal center. The formula is \([CoCl_2(en)_2]^+\), where the complex ion has a +1 charge, balanced by a counterion.

Hence, the correct answer is option 2. (A)-(IV), (B)-(III), (C)-(II), (D)-(I).