The coordination number and oxidation state of Cr in K₃[Cr(C₂O₄)₃] are respectively

1. 3 and +3

2. 3 and 0

3. 6 and +3

4. 4 and +2

The coordination number of cobalt in[Co(en)₂Br₂]Cl₂ is:

1. 2

2. 4

3. 6

4. 8

A solution containing 2.675 g of CoCl₃.6NH₃ (molar mass = 267.5 g mol^-1) is passed through a cation exchanger. The chloride ions obtained in the solution were treated with an excess of AgNO₃ to give 4.78 g of AgCl. Formula of the complex is (Atomic mass of Ag = 108u) :

1. [CoCl(NH₃)₅]Cl₂

2. $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]{\mathrm{Cl}}_3$

3. [CoCl₂(NH₃)₄]Cl

4. [CoCl₃(NH₃)₃]

The primary valency of Fe in K₃[Fe(CN)₆] is:

1. 3

2. 2

3. 1

4. zero

The compound 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]