The hybridisation and geometry of $[Ni(CN)_4]^{2-}$ are:

Complexes $(ML_5)$ of metals $Ni$ and $Fe$ have ideal square pyramidal and trigonal bipyramidal geometries,respectively. The sum of the $90^{\circ}$,$120^{\circ}$ and $180^{\circ}$ $L-M-L$ angles in the two complexes is

The geometries of some complex ions are given below. Select the correct answer.
$(1) [Ag(NH_3)_2]^+ - \text{Linear}$
$(2) [MnCl_4]^{2-} - \text{Tetrahedral}$
$(3) [Cu(NH_3)_4]^{2+} - \text{Square planar}$
$(4) [Ni(CN)_4]^{2-} - \text{Square planar}$

The coordination complex $[Co(OH_2)_6]^{2+}$ has one unpaired electron. Which of the following statements are true?
$(i)$ The complex is octahedral.
$(ii)$ The complex is an outer orbital complex.
$(iii)$ The complex is diamagnetic.

What type of hybridisation is present in square planar geometry of complex $[Ni(CN)_4]^{2-}$?

Addition of excess potassium iodide solution to a solution of mercuric chloride gives the halide complex