The complex ion `[Co(NH_(3))_(5)Cl^(2+)(X)` undergoes a substitution reaction when reacted with `(NaNO_(2)+HCl)` An unstable scarlet red complex A is formed when dilute acid is used and a stable yellow complex `B` is formed when concentrated acid is used Both `A` and `B` are isomeric pentammine complex ions Give the structures of the ions und name the type of the isomerism involved .

Explanation

Since the treatment of`(X) (NaNO_(2)+ dil HCI)` gives as unstable red coplex should be pentaamminenitritocobalt (III) ion `[Co^(3+(NH_(3))_(5)(ONO)]^(2+)`
Similarly the ion obtained by treating `[Co^(3+)(NH_(3))_(5)CI]^(2+)(X)` ion with `(NaNO_(2) + conc.HCI)` should be pentaammine nitrocobalt (III) ion `[Co^(3+)(NH_(3))(NH_(3))_(5)(NO_(2))]^(2+)`
Thus `A = [Co^(3+)(NH_(3))_(5)(ONO)]^(2+)` and
`B = [Co^(3+)(NH_(3))_(5)(No_(2))]^(2+)`
Obviously `A` and `B` linking isomers and the isomerism involved is linkage isomerism .