MCQ
Which of the following complex is paramagnetic and inner orbital complex
- A$[Fe(CN)_6]^{4-}$
- ✓$[Cr(NH_3)_6]^{3+}$
- C$[Co(NH_3)_6]^{3+}$
- D$[Fe(NO_2)_6]^{4-}$
The electronic configuration of ${ }_{27} Co =1 s ^2, 2 s ^2, 2 p ^6, 3 s ^2 3 p ^6 3 d ^7, 4 s ^2$
$Co ^{3+}=1 s^2 2 s^2 2 p^6, 3 s^2 3 p^6 3 d^6$
Thus, $\left[ Co \left( NH _3\right)_6\right)^{3+}$ shows inner orbital complex as well as diamagnetic in behaviour (due to absence of an unpaired electron).
$\left[ Zn \left( NH _3\right)_6\right]^{2+} \rightarrow sp ^3 d ^2$ hybridisation (outer) and diamagnetic.
$\left[ Cr \left( NH _3\right)_6\right]^{3+} \rightarrow d ^2 sp ^3$ hybridisation (inner) and paramagnetic.
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$(A)$ Freezing of water to ice at $0^{\circ} C$
$(B)$ Freezing of water to ice at $-10^{\circ} C$
$(C)$ $N _{2}( g )+3 H _{2}( g ) \rightarrow 2 NH _{3}( g )$
$(D)$ Adsorption of $CO ( g )$ and lead surface
$(E)$ Dissolution of $NaCl$ in water