Question

LIST-I contains metal species and LIST-II contains their properties.

LIST-I	LIST-II
I	$\text{[Cr(CN)}_6\text{]}^{4-}$
II	$\text{[RuCl}_6\text{]}^{2-}$
III	$\text{[Cr(H}_2\text{O)}_6\text{]}^{2+}$
IV	$\text{[Fe(H}_2\text{O)}_6\text{]}^{2+}$
	T

[Given : Atomic number of Cr = 24, Ru = 44, Fe = 26]
Metal each metal species in LIST-I with their properties in LIST-II, and choose the correct option.

• A. I → R, T; II → P, S; III → Q, T; IV → P, Q
• B. I → R, S; II → P, T; III → P, Q; IV → Q, T
• C. I → P, R; II → R, S; III → R, T; IV → P, T
• D. I → Q, T; II → S, T; III → P, T; IV → Q, R

Answer 1

Answer: (A)

I → R, T; II → P, S; III → Q, T; IV → P, Q

Answer 2

(I) $\text{[Cr(CN)}_6\text{]}^{4-}$

The Cr2+ ion, with the electron configuration [Ar] 3d4 4s0, undergoes d2sp3 hybridization due to the strong field ligand CN–.

(II) $\text{[RuCl}_6\text{]}^{2-}$:

The Ru4+ ion, with the electron configuration [Kr] 4d4 5s0, has a t2g set that contains four electrons.

(III) $\text{[Cr(H}_2\text{O)}_6\text{]}^{2+}$:

The Cr2+ ion, with the electron configuration [Ar] 3d4 4s0, exhibits four unpaired electrons due to the weak field ligand H2O, resulting in a magnetic moment of 4.9 B.M.

(IV) $\text{[Fe(H}_2\text{O)}_6\text{]}^{2+}$

The Fe2+ ion, with the electron configuration [Ar] 3d6 4s0, also possesses four unpaired electrons, resulting in a magnetic moment of 4.9 B.M.
Hence option A is Correct