[Cr(NH₃)₆]³⁺ is paramagnetic ,while ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$ is diamagnetic because:

1.	Electrons in the 3d orbitals remain unpaired in ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$
2.	Electrons in the 3d orbitals remain unpaired in [Cr(NH3)6]3+
3.	Electrons in the 3p orbitals remain unpaired in [Cr(NH3)6]3+
4.	Electrons in the 3p orbitals remain unpaired in ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$

$1.$ ${\mathrm{K}}_2\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$
$2.$ ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$
$3.$ ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_2\right]$
$4.$ ${\mathrm{K}}_2\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_4\right]$

The correct splitting diagram of d orbitals in an octahedral crystal field is:

1.		2.
3.		4.	None of these.

Optical isomerism is exhibited by among the following is/are:

Ethylene diaminetetraacetate (EDTA) ion is:

Given below are two statements :

1. Statement I is false but Statement II is true.

2. Both Statement I and Statement II are false.

3. Statement I is true but Statement II is false.

4. Both Statement I and Statement II are true.

For a ${\mathrm{d}}^4$ metal ion in an octahedral field, the correct electronic configuration is:

The complex that will exhibit maximum ionic conductivity in aqueous solution is:

1. K₄[Fe(CN)₆]

2. [Co(NH₃)₆]Cl₃

3. [Cu(NH₃)₄]Cl₂

4. [Ni(CO)₄]

A metal ion present in vitamin B₁₂ is: