(i) What type of isomerism is shown by the complex `[Co(NH_(3))_(6)] [Cr(CN)_(6))]` ?
(ii) Why a solution of `[Ni(H_(2)O)_(6)^(2+)` is given while a solution of `[No(CN)_(4)]^(2-)` colourless ? (At. No. of Ni = 28)
(iii) Write the IUPAC name of the following complex : `[Co(NH_(3))_(5) (CO_(3))] Cl`

Explanation

(i) Coordination isomerism is shown by the complex
`[Co(NH_(3))_(6) [Cr(CN)_(6)] and [Cr (NH_(3))_(6)] [Co(CN)_(6)]`
(ii)
In case of `[Ni(H_(2)O)_(6)]^(2+), 2` unpaired electrons are present wherease in `[Ni(CN)_(6)]^(2-)`, there is no free electrons because of the presence of strong field ligand. Hence, `[Ni(H_(2)O)_(6)]^(2+)` solution is green in colour, while a solution of `[Ni(CN)_(4)]` is colourless because of the absence of unpaired electrons. The unpaired electrons in `[Ni(H_(2)O)_(6)]^(2+)` absorb energy and get excited to high energy level and come back to lower energy level an impart colour
(iii) `[Co(NH_(3))_(5) (CO)_(3)] Cl`- Pentaamminecarbonatocobalt (iii) chloride