Which statement about the co-ordination number of a cation is true?

(1)  Metal ions exhibit only a single characteristic co-ordination number

(2)  The co-ordination number is equal to the number of ligands bonded to the metal atom

(3)  The co-ordination number is determined solely by the number of empty d-orbitals in the atom

(4)  Co-ordination number is equal to the number of coordinate bonds between the metal cation and ligands

If ${\mathrm{Cd}}^{2+}$ and ${\mathrm{Cu}}^{2+}$ both are present, both are complexed by ${\mathrm{CN}}^{-}$ and ${\mathrm{H}}_2\mathrm{S}$ gas is passed, which one of the following pairs of complexes and their relative stability enables the separation of ${\mathrm{Cu}}^{2+}$ and ${\mathrm{Cd}}^{2+}$?

1.  ${\mathrm{K}}_3\left[\mathrm{Cu}\left({\mathrm{CN}}_4\right)\right]$: more stable and ${\mathrm{K}}_2\left[\mathrm{Cd}\left({\mathrm{CN}}_4\right)\right]$: less stable

2.  ${\mathrm{K}}_2\left[\mathrm{Cu}\left({\mathrm{CN}}_4\right)\right]$: less stable and ${\mathrm{K}}_2\left[\mathrm{Cd}\left({\mathrm{CN}}_4\right)\right]$: more stable

3.  ${\mathrm{K}}_2\left[\mathrm{Cu}\left({\mathrm{CN}}_4\right)\right]$: more stable and ${\mathrm{K}}_2\left[\mathrm{Cd}\left({\mathrm{CN}}_4\right)\right]$: more stable

4.  ${\mathrm{K}}_3\left[\mathrm{Cu}\left({\mathrm{CN}}_4\right)\right]$: less stable and ${\mathrm{K}}_2\left[\mathrm{Cd}\left({\mathrm{CN}}_4\right)\right]$: more stable

The spin-only magnetic moments of ${\left[\mathrm{Mn}{\left(\mathrm{CN}\right)}_6\right]}^{4-}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\left[{\mathrm{MnBr}}_4\right]}^{2-}$ in Bohr Magnetons, respectively, are

1.  5.92 and 5.92

2.  4.89 and 1.73

3.  1.73 and 5.92

4.  1.73 and 1.73

The crystal field stabilization energies (CFSE) of high spin and low spin $d^6$ metal complexes in terms of ${∆}_0$, respectively are

1.  -0.4 and -2.4

2.  -2.4 and -0.4

3.  -0.4 and 0.0

4.  -2.4 and 0.0

For a tetrahedral complex [MCl₄]^2-, the spin-only magnetic moment is 3.83 B.M. The element M is:

1. Co

2. Cu

3. Mn

4. Fe

Among the following, the species that is both tetrahedral and diamagnetic is

1.  ${\left[{\mathrm{NiCl}}_4\right]}^{2-}$

2.  ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$

3.  $\left[\mathrm{Ni}{\left(\mathrm{CO}\right)}_4\right]$

4.  ${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$

The number of ions produced in water by the dissolution of the complex $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]\mathrm{CI}$ having the empirical formula is

1.  1

2.  2

3.  4

4.  3

In aqueous solution, ${\left[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ (X) reacts with molecular oxygen in the presence of excess liquor $N{H}_3$ to give a new complex Y. The number of unpaired electrons in X and Y are, respectively

1.  3,1

2.  3,0

3.  3,3

4.  7,0 

The number of geometrical isomers of $\left[{\mathrm{CrCI}}_2\left(\mathrm{en}\right){\left({\mathrm{NH}}_3\right)}_2\right]$, where en = ethylenediamine, is

1.  2

2.  3

3.  4

4.  1

The energies of ${\mathrm{d}}_{\mathrm{xy}} \mathrm{and} {{\mathrm{d}}_{\mathrm{z}}}^2$ orbitals in octahedral and tetrahedral transition metal complexes are such that

1.  $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) > \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$ in both tetrahedral and octahedral complexes

2.  $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) < \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$ in both tetrahedral and octahedral complexes

3.  $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) > \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$ in tetrahedral but $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) < \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$ in octahedral complexes

4.   $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) < \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$  in tetrahedral but $\mathrm{E}\left({\mathrm{d}}_{\mathrm{xy}}\right) > \mathrm{E}\left({\mathrm{d}}_{{\mathrm{z}}^2}\right)$ in octahedral complexes