The complex \([Co(NH_3)_4(NO_2)_2]Cl\) exhibits

1. Coordination isomerism
2. Linkage isomerism
3. Solvate isomerism
4. Ionization isomerism
5. Geometrical isomerism

Choose the correct answer from the options given below:

B, D and E only

The complex \([Co(NH_3)_4(NO_2)_2]Cl\) exhibits linkage isomerism, ionization isomerism, and geometrical isomerism.

Linkage isomerism arises from the possibility of different modes of bonding between the central metal ion \((Co)\) and the ligands (\(NH_3\) and \(NO_2\)). In this case, the \(NO_2\) ligand can bond to the \(Co\) ion through either the nitrogen atom \((N)\) or the oxygen atom \((O)\). This results in two linkage isomers:

\([Co(NH_3)_4(NO_2)(ONO)]Cl\) and  \([Co(NH_3)_4(ONO)(NO_2)]Cl\)

Ionization isomerism arises from the dissociation of the complex ion to form different ionic species. In this case, the \([Co(NH_3)_4(NO_2)_2]Cl\) complex can ionize to form either \([Co(NH_3)_4(NO_2)Cl]NO_2\) or \([Co(NH_3)_4(NO_2)_2]Cl\).

Geometrical isomerism arises from the different spatial arrangements of the ligands around the central metal ion. In this case, the \([Co(NH_3)_4(NO_2)_2]Cl\) complex can exist in two geometrical isomers:

\(cis-[Co(NH_3)_4(NO_2)_2]Cl\) and  \(trans-[Co(NH_3)_4(NO_2)_2]Cl\)

Therefore, the correct answer is 1. B, D and E only.