Question

Match the column I with column II and mark the appropriate choice.

Column I		Column II
(A)	$\lbrack Fe(CN)_{6}\rbrack^{3 -}$	(i)	Zero
(B)	$\lbrack CoF_{6}\rbrack^{3 -}$	(ii)	$5.92B.M.$
(C)	$\lbrack Fe(H_{2}O)_{6}\rbrack^{3 +}$	(iii)	$4.86B.M.$
(D)	$\lbrack Co(NH_{3})_{6}\rbrack^{3 +}$	(iv)	$1.732B.M$

• A. (A) $\rightarrow$ (ii), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (iv),(D) $\rightarrow$ (i)
• B. (A) $\rightarrow$ (iii), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (i),(D) $\rightarrow$ (iv)
• C. (A) $\rightarrow$ (i), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (iv),(D) $\rightarrow$ (ii)
• D. (A) $\rightarrow$ (iv), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (ii),(D) $\rightarrow$ (i)

Answer 1

Answer: (D)

(A) $\rightarrow$ (iv), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (ii),(D) $\rightarrow$ (i)

Answer 2

$Fe^{3 +};3d^{5},$ since $CN^{-}$is a strong field ligand, pairing will take place.

$\lbrack Fe(CN)_{6}\rbrack^{3 -}:$ Fig [$\because$n = 1]

$\mu = \sqrt{n(n + 2)} = \sqrt{1(1 + 2)} = \sqrt{3} = 1.732B.M.$

In $\lbrack CoF_{6}\rbrack^{3 -}$Oxidations state of Co = +3

$Co^{3 +}:3d^{6}$since $F^{-}$is a weak field ligand, pairing will not occur.

$\mu = \sqrt{4(4 + 2)} = \sqrt{24} = 4.86B.M.$

In $\lbrack Fe(H_{2}O)_{6}\rbrack^{3 +},$ Oxidations state of Fe = +3

$Fe^{3 +}:3d^{5},$ since $H_{2}O$is a weak filed ligand, pairing will not take place.

$\mu = \sqrt{5(5 + 2)} = \sqrt{35} = 5.92B.M.$

In $\lbrack Co(NH_{3})_{6}\rbrack^{3 +},$ Oxidations state of Co = +3.

$Co^{3 +}:3d^{6},$ since$NH_{3}$is a strong field ligand, pairing will take place.

$\mu = \sqrt{0(0 + 2)} = 0$