Which of the following complexes has a square planar geometry?

$A$ coordination compound is made of $Co^{3+}$,$NH_3$,and $Cl^{-}$. $A$ $0.1 \ M$ solution of this complex when treated with excess silver nitrate gave no precipitate. The formula of the complex and secondary valency of metal are respectively.

Which of the following complex ions has $0$ $d$-electrons in the central metal atom? (Atomic numbers: $Cr = 24, Mn = 25, Fe = 26, Co = 27$)

The tetracyanonickelate $(II)$ complex ion has a ..... geometry.

The hexafluoroferrate $(II)$ ion is an outer orbital complex. The number of unpaired electrons in it is .............

Match the hybridisation in Column $I$ with the complexes in Column $II$. The options represent the matches for $(A), (B), (C), (D)$ respectively.

Column $I$	Column $II$
$(A)$ $sp^3$	$(i)$ $[Co(NH_3)_6]^{3+}$
$(B)$ $dsp^2$	$(ii)$ $[Ni(CO)_4]$
$(C)$ $sp^3d^2$	$(iii)$ $[Pt(NH_3)_2Cl_2]$
$(D)$ $d^2sp^3$	$(iv)$ $[CoF_6]^{3-}$
	$(v)$ $[Fe(CO)_5]$