Question

a. Using, Valence Bond Theory identify A, B, C, D, E and F in the following table:

S. No.	Complex	Central metal in	Configuration of metal ion	Hybridization of Metal ion	Geometry of the Complex	Number Of Unpaired Electron	Magnetic Behaviour
i.	\[\ce{[CoF4]^{2-}}\]	\[\ce{A}\]	3d7	sp3	tetrahedral	B	Paramagnetic
ii.	\[\ce{[Cr(H2O)2(C2O4)2]}\]	\[\ce{Cr^{3+}}\]	3d3	C	octahedral	3	D
iii.	\[\ce{[Ni(CO)4]}\]	\[\ce{Ni}\]	3d84s2	E	F	0	Diamagnetic

b. Write the ionic equations for the reaction of acidified \[\ce{K2Cr2O7}\] with

1. \[\ce{H2S}\] and
2. \[\ce{FeSO4}\]

Answer 1

a.

S. No.	Complex	Central metal in	Configuration of metal ion	Hybridization of Metal ion	Geometry of the Complex	Number Of Unpaired Electron	Magnetic Behaviour
i.	\[\ce{[CoF4]^{2-}}\]	\[\ce{Co^{2+}}\]	3d7	sp3	tetrahedral	3	Paramagnetic
ii.	\[\ce{[Cr(H2O)2(C2O4)2]}\]	\[\ce{Cr^{3+}}\]	3d3	d2sp3	octahedral	3	Paramagnetic
iii.	\[\ce{[Ni(CO)4]}\]	\[\ce{Ni}\]	3d84s2	sp3	tetrahedral	0	Diamagnetic

b.

1. \[\ce{Cr2O^{2-}7 + 8H+ + 3H2S -> 2Cr^{3+} + 3S + 7H2O}\]
2. \[\ce{Cr2O^{2-}7 + 14H+ + 6Fe^{2+} -> 2Cr^{3+} + 6Fe^{3+} + 7H2O}\]