KVPY Sample Paper KVPY Stream-SX Model Paper-20

Among the following complexes (K-P)

\[{{K}_{3}}[Fe{{(CN)}_{6}}](\mathbf{K}),[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}(\mathbf{L}),\]

\[N{{a}_{3}}[Co{{(oxalate)}_{3}}](\mathbf{M}),[Ni{{({{H}_{2}}O)}_{6}}]C{{l}_{2}}(\mathbf{N})\]

\[{{K}_{2}}[Pt{{(CN)}_{4}}](O)\]and\[[Zb{{({{H}_{2}}O)}_{6}}]{{(N{{O}_{3}})}_{2}}(\mathbf{P})\]

the diamagnetic complexes are

A) K, L, M, N

B) K, M, O, P

C) L, M, O, P

D) L, M, N, O

Correct Answer: C

Solution :

Complex	No. of electrons in outer\[d\]orbital	No. of unpaired electron (s)
\[{{[Fe{{(CN)}_{6}}]}^{3-}}\]	\[3{{d}^{5}}\]	1(\[{{\operatorname{CN}}^{-}}\]causes pairing of electrons)
\[{{[Co{{(N{{H}_{3}})}_{6}}]}^{3+}}\]	\[3{{d}^{6}}\]	0
\[{{[Co{{(ox.)}_{3}}]}^{3-}}\]	\[3{{d}^{6}}\]	0
\[{{[Ni{{({{H}_{2}}O)}_{6}}]}^{2+}}\]	\[3{{d}^{8}}\]	2
\[{{[Pt{{(CN)}_{4}}]}^{2-}}\]	\[5{{d}^{8}}\]	0(\[{{\operatorname{CN}}^{-}}\]causes pairing of electrons)
\[{{[Zn{{({{H}_{2}}O)}_{6}}]}^{2+}}\]	\[3{{d}^{10}}\]	0

Thus, L, M, O and P are diamagnetic.