The oxidation number and coordination number of Co in the complex K₃[Co(C₂O₄)₃] respectively are:

1.	+3, 6	2.	+2, 6
3.	6, +3	4.	+2, 4

The correct IUPAC name of the complex K[Cr(H₂O)₂(C₂O₄)₂].3H₂O is:

1. Potassiumdiaquadioxalatochromate(III)trihydrate

2. Diaquadioxalatopotassiumchromate (III) trihydrate

3. Potassiumdihydridodioxalatochromate(IV)trihydrate

4. Potassiumdiaquadioxalatochromate(II)trihydrate

Number of ions produced from the complex [Co(NH₃)₆]Cl₂ in an aqueous solution are:

1. 6      

2. 4    

3. 3        

4. 2

The compound with the highest magnetic moment value is:

1. \( {\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}} \)
2. \( {\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}} \)
3. \({\left[\mathrm{Zn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}} \)
4. \( {\left[\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}}\)

The oxidation number of Cobalt in K[Co(CO)₄] is :

1. +1       

2. +3         

3. –1         

4. –3

 The most stable complex among the following is:

1. [Fe(H₂O)₆]³⁺     

2. [Fe(NH₃)₆]³⁺       

3. [Fe(C₂O₄)₃]^3–       

4. [FeCl₆]^3–

What is the overall complex dissociation equilibrium constant for the ${\left[\mathrm{Cu}\right({\mathrm{NH}}_3\left)\right]}^{2+}$ ion , given that ${\mathrm{\beta }}_{4 }$for this complex is $2.1 \times {10}^{13}$ ?

$1. 4.7 \times {10}^{-14}$
$2. 3.6 \times {10}^{-12}$
$3. 4.9 \times {10}^{14}$
$4. 5.6 \times {10}^{-13}$

Indicate the complex ion that shows geometrical isomerism:
1. [Cr(H₂O)₄ Cl₂]⁺
2. [Pt(NH₃)₃ Cl]
3. [Co(NH₃)₆]³⁺
4. [Co(CN)₆]^3-

The hybridisation of [FeF₆]^3- is: