Among the following the most stable complex is

• [Fe(H₂O)₆]³⁺

• [Fe(NH₃)₆]³+

• [Fe(C₂O₄)₃]^3–
• [FeCl₆]^3–

How many ions are produced from complex [Co(NH₃)₆]Cl₂ in solution?

• 6

• 4

• 3

• 2

The complex ion which has no 'd' electrons in the central metal atom is

• [MnO₄]^– 
• [Co(NH₃)₆]³⁺
• [Fe(CN)₆]^3– 
• [Cr(H₂O)₆]³⁺

Which of the following complex will not show colour?

• K₃[VF₆] 
• [Cr(NH₃)₆]Cl₃
• [Sc(H₂O)₆]³⁺
• [NiCl₄]^2–

A group of atoms can function as a ligand only when

• It is a small molecule

• It has an unshared electron pair

• It is negatively charged ion

• It is positively charged ion. 

The number of ions formed when cuprammonium sulphate is dissolved in water is

• 1

• 2

• 4

• zero

Which complex has square planar structure?

• Ni(CO)₄
• [NiCl₄]^2-
  

• [Ni(CN)₄]^2–

• [Cu(NH₃)₄]²⁺

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

• +1

• +3

• -1

• -3

What type of geometrical shape the following types of hybrid orbitals have? (a) d²sp³, (b) dsp^2.