Question

The correct IUPAC name of $[Pt{(N{H_3})_2}C{l_2}]$ is:
A. Diamminedichloridoplatinum $(II)$
B. Diamminedichloroplatinum $(IV)$
C. Diamminedichloroplatinum $(0)$
D. Dichlorodiammineplatinum $(V)$

Answer 1

The given compound is a coordination compound. Coordination compounds are the one which contain one or more metal atoms which are bonded to one or more ligands. The ligands donate its electrons to the metal atom. Here two types of ligands are present. $N{H_3}$ is a neutral ligand and $Cl$ is an anionic ligand.

Complete answer:
We will first name the ligands in alphabetical order. We will use di, tri, tetra etc. if the same type of ligands is present in a compound. If two ligands of the same type are present, we will use di, if three ligands of same type are present in a compound, we will use tri and so on for the rest.
Here we see that two $N{H_3}$ ligands and two $Cl$ ligands are present in a compound so we will use di.
So ${(N{H_3})_2}$ will be named as diamine and $C{l_2}$ will be named as dichloride. Also, as ligands are named in alphabetical order ammine will therefore come before chloride.
Now we need to find the oxidation state of the metal atom present i.e. platinum.
As $N{H_3}$ is a neutral ligand so its oxidation state will be $0$ and $Cl$ is a negatively charge ligand so it will have an oxidation state of $( - 1)$
Hence the oxidation state of platinum will be:
let the oxidation state of $Pt$ be $x$
so,
$x + 0 \times 2 + 2 \times ( - 1) = 0 \\\ \Rightarrow x = 0 - 2 = 0 \\\ \Rightarrow x - 2 = 0 \\\ \Rightarrow x = + 2$
Hence the oxidation state of $Pt$ is $+ 2$
Therefore, the IUPAC name of $[Pt{(N{H_3})_2}C{l_2}]$ $=$ Diamminedichloridoplatinum $(II)$

**Thus, the correct answer is Option A.

Note:**
Here we take $x + 0 - 2 = 0$ i.e. the sum of all the oxidation states of ligands and metals in a compound are taken as zero as this is a neutral compound. Generally, coordination compounds are neutral compounds. By looking at the number of ligands attached to the central metal atom we can easily determine the coordination number of the central metal. Here in $[Pt{(N{H_3})_2}C{l_2}]$ the coordination number of platinum is four as four ligands are attached to it.