Question

The formula of the complex diammine dichloro-(ethylenediamine) nitro platinum $\left( IV \right)$ chloride is:
(A) $[Pt{{(N{{H}_{3}})}_{2}}Cl(en)N{{O}_{2}}]C{{l}_{2}}$
(B) $[Pt{{(N{{H}_{3}})}_{2}}(en)C{{l}_{2}}N{{O}_{2}}]Cl$
(C) $[Pt{{(N{{H}_{3}})}_{2}}(en)N{{O}_{2}}]C{{l}_{2}}$
(D) $[Pt{{(N{{H}_{3}})}_{2}}(en)N{{O}_{2}}C{{l}_{2}}]$

Answer 1

We know that coordination compounds are neutral substances having a metal with one or more ligands. The ligands may be anionic, cationic or neutral. The charge must be balanced on the complex. There are certain rules provided by IUPAC for their naming.

Complete answer:
As per the IUPAC nomenclature rule, for naming a coordination compound, ligands are first numbered and then mention the metal name with the oxidation state in brackets. For ligands naming such as ionic ligands: chloride is chloride, sulphate is sulphate, nitrate is nitrato, etc. whereas for neutral ligands like water is aqua, carbon monoxide is carbonyl, ammonia is ammine, etc.
If the overall complex is negatively charged then the metal’s name ends with ‘ate’. For example, iron as ferrate, copper as cuprate, platinum as platinate, gold as aurate, etc. but in case of neutral or positively charged complexes, the metal’s name remains as it is. Cobalt will be cobalt in tris(ethane $-1,2-$ diamine) cobalt (III) sulphate where the oxidation state of copper is $+3.$
The formula of the complex diammine dichloro-(ethylenediamine) nitro platinum $\left( IV \right)$ chloride is $[Pt{{(N{{H}_{3}})}_{2}}Cl(en)N{{O}_{2}}]C{{l}_{2}}$ ​. Because the ligands $-~N{{H}_{3}}$ ​ and ethylenediamine (en) are neutral ligands whereas Chlorine $\left( C{{l}^{-}} \right)$ and Nitro $\left( NO_{2}^{-} \right)$ have negative charge of $-1$ on them. Thus, the only compound which forms a Platinum complex with metal ion oxidation state $\left( IV \right)$ is option (A).
Hence, option (A) is the correct answer.

Note:
Remember that there are more rules for nomenclature such as for bridging ligands, which are used as a prefix. . The directly attached ligands are always placed before the metal ion. If more than one ligand is present, then they are named in alphabetical order.