Ethylene diaminetetraacetate (EDTA) ion is:

The correct order of increasing field strength of ligands is:

1. ${\mathrm{SCN}}^{- }< {\mathrm{F}}^{- }< {\mathrm{CN}}^{- }< {\mathrm{C}}_2{\mathrm{O}}_4^{2-}$

2. ${\mathrm{F}}^{- }< {\mathrm{SCN}}^{- }< {\mathrm{C}}_2{\mathrm{O}}_4^{2- }< {\mathrm{CN}}^{-}$

3. ${\mathrm{CN}}^{- }< {\mathrm{C}}_2{\mathrm{O}}_4^{2- }< {\mathrm{SCN}}^{- }< {\mathrm{F}}^{-}$

4. ${\mathrm{SCN}}^{- }< {\mathrm{F}}^{- }< {\mathrm{C}}_2{\mathrm{O}}_4^{2- }< {\mathrm{CN}}^{-}$

A complex  ion among the following can absorb visible light is:
(At. no. Zn = 30, Sc = 21, Ti = 22, Cr = 24)

1. [Sc(H₂O)₃(NH₃)₃]³⁺

2. [Ti(en)₂ (NH₃)₂]⁴⁺

3. [Cr(NH₃)₆]³⁺

4. [Zn(NH₃)₆]²⁺

Which of the following complexes has the highest paramagnetic behaviour?

(where gly = glycine, en = ethylenediamine, ox = oxalate ion and bpy = bipyridyl moieties )
(At no : Ti= 22, V = 23, Fe = 26, Co = 27)

1. [V(gly)₂(OH)₂(NH₃)₂]⁺

2. [Fe(en)(bpy)(NH₃)₂]²⁺

3.  [Co(ox)₂(OH)₂]^-

4. [Ti(NH₃)₆]³⁺

CFSE (in the octahedral field) will be maximum in:
(Atomic number Co = 27)

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

2. ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$

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

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

CN^– is a strong field ligand. This is due to the fact that:

1. It is a pseudohalide.

2. It can accept electrons from metal species.

3. It forms high-spin complexes with metal species.

4. It carries a negative charge.