What is the color of the complex $[Co(H_2O)_6]Cl_3$?

Match the following:

List-$I$ (Hybridisation)	List-$II$ (Compound/ion)
$A. sp^3d$	$I. [PtCl_4]^{2-}$
$B. sp^3d^2$	$II. SF_6$
$C. dsp^2$	$III. BCl_3$
$D. dsp^3$	$IV. PCl_5$
	$V. ClF_3$

The correct match is:

Which of the following ions is not tetrahedral?

When excess of ammonia is added to copper sulphate solution,the deep blue coloured complex is formed. The complex is

The metal $Ni$ $(Z = 28)$ combines with a unidentate ligand $X^-$ to form a paramagnetic complex $[NiX_4]^{2-}$. What are its geometry and the number of unpaired electrons in $Ni$?

The type of hybridization involved in the metal ion of the $[Ni(H_2O)_6]^{2+}$ complex is: