Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following :
(i) \([CoF_6]^{3-}, [Co(H_2O)_6]^{2+},[Co(CN)_6]^{3-}\) 
(ii) \([FeF_6]^{3-}, \ [Fe(H_2O)_6]^{2+}, [Fe(CN)_6]^{4-}\).

Using valence bond theory, explain the following in relation to the complexes given below :
\([Mn(CN)_6]^{3-}, [Co(NH_3)_6]^{3+}, [Cr(H_2O)_6]^{3+}, [FeCl_6]^{4-}\)
(i) Type of hybridisation    
(ii) Inner or outer orbital complex.    
(iii) Magnetic behaviour.    
(iv) Spin only magnetic moment value.

CoSO₄Cl.5 NH₃ exists in two isomeric forms 'A' and 'B' gives white precipitate with BaCl₂ but does not react with AgNO₃.  Answer the following questions.
(i) Identify 'A' and 'B' and write their structure formulas.    
(ii) Name the type of isomerism involved    
(iii) Give the IUPAC name of 'A' and 'B'.

What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex ?

Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands ?

Just like human beings, plants also need various nutrients for their healthy growth. Iron is one of these. The deficiency of iron results in disorder known as iron chlorosis. It appears in the form of yellow leaves. It adversely affect the yield of fruits from citrus trees.
(i) In which oxidation state is iron generally present in the soil?
(ii) Why is iron hydroxide not assimilated in the soil?
(ill) Which complex of iron is readily absorbed by soil?
(iv) What can you suggest to stop the adverse effect of iron deficiency?

Co-ordination compounds have an important role in the field of medicines. Out of these, the compound cis-platin is quite effective against cancer. It inhibits the growth of tumors leading to cancer.
(i) What is the chemical formula and name of the complex?
(ii) How does it behave as an anti cancer agent?
(iii) Why is trans-isomer not effective?
(iv) What is the value associated with the use of cis platin?