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

The geometry and magnetic properties of [NiCl₄]^2-, respectively, are : 

1. Tetrahedral, Paramagnetic

2. Tetrahedral, Diamagnetic

3. Square planar, Paramagnetic

4. Square planar, Diamagnetic  

Among the following, the compound that has the maximum coordination number is/are:

1. [Co(NH₃)₆]³⁺
2. [Cr(C₂O₄)₃]^3-
3. [CoCl₃(H₂O)₃]
4. All of the above have the same coordination number

The complex that can exhibit linkage isomerism is:

A person having osteoporosis is suffering from lead poisoning. Ethylenediamine tetraacetic acid (EDTA) is administered for this condition. The best form of EDTA to be used for such administration is:

1. EDTA

2. Tetrasodium salt

3. Disodium salt

4. Calcium dihydrogen salt

The complex that can exhibit optical activity among the following is:

1. [CoCl₆]^3-

2. [Co(en)CI₄]^-

3. cis-[Co(en)₂Cl₂]⁺

4. trans-[Co(en)₂Cl₂]⁺ 

The oxidation state of cobalt in the following molecule is:

1. 3

2. 1

3. 2

4. 0

The complex ion among the following that cannot absorb visible light is:

1. [Ni(CN)₄]^2-

2. [Cr(NH₃)₆]³⁺

3. [Fe(H₂O)₆]²⁺

4. [Ni(H₂O)₆]²⁺

The most stable complex among the following species is:

1.  $\left[\mathrm{Fe}{\left(\mathrm{CO}\right)}_5\right]$

2.  $[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{3-}$

3.  $[\mathrm{Fe}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3{]}^{3-}$

4.  $[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6{]}^{3+}$