Match List-I (Complex/ion) with List-II (Shape/geometry): List-I (a) \ce{[PtCl2(NH3)2]} (b) \ce{[Co(NH3)6]Cl3} (c) \ce{[NiCl4]^2-} (d) \ce{[Fe(CO)5]} List-II (i) Octahedral (ii) Trigonal bipyramidal (iii) Square planar (iv) Tetrahedral Choose the correct option:

Solution & Explanation

\textbf{Answer:} (B) (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii). \textbf{Solution:} Geometry follows from hybridisation in each case: (a) \ce{[PtCl2(NH3)2]}: Pt(II), $5d^8$, strong-field $\Rightarrow$ $dsp^2$ $\Rightarrow$ \textbf{square planar} (iii). (b) \ce{[Co(NH3)6]^3+}: Co(III), $3d^6$, \ce{NH3} strong-field $\Rightarrow$ $d^2sp^3$ $\Rightarrow$ \textbf{octahedral} (i). (c) \ce{[NiCl4]^2-}: Ni(II), $3d^8$, weak-field \ce{Cl-} $\Rightarrow$ $sp^3$ $\Rightarrow$ \textbf{tetrahedral} (iv). (d) \ce{[Fe(CO)5]}: Fe(0), $sp^3d$ (also written $dsp^3$) $\Rightarrow$ \textbf{trigonal bipyramidal} (ii). Thus (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii), option (B).