Question

The IUPAC name of ${K_2}[Zn{(OH)_4}]$ is
A. Potassium tetrahydroxozincate(II)
B. Potassium tetrahydroxyzincate(II)
C. Potassium tetrahydroxyzincate(VI)
D. Potassium hydroxy zinc(II)

Answer 1

The above compound is a coordination compound which consists of an array of anions or neutral molecules that are bound to a central atom via covalent bond. In such cases, IUPAC Nomenclature states that cation is named first followed by the complex formed along with the anionic outside the bracket( if any) at the end while naming the compound.

Step by step answer: Following the IUPAC nomenclature the name of the cation or the counter ion which is potassium in our case will be written first before the name of the complex ion. In a coordination complex the atoms which are bound to the central atom are called ligands.
In the IUPAC nomenclature the ligands are always written before the central atom. If there are many polydentate ligands attached to the central metal ion the nomenclature goes as bis, tris, tetra and so on.
Along with this the name of the anion in the coordination compound ust end with the letter ‘o’. Here in our case it contains $4OH -$ groups so it will be tetrahydroxy. After the ligand nomenclature the central atom is named and if there is present any anionic charge the central atom is added with the suffix ‘ate’. If we determine the oxidation number of zinc by charge balance it comes out at zinc(II).

Therefore If we combine the name we will get it as Potassium tetrahydroxozincate(II).

Therefore the correct option is Option(B), Potassium tetrahydroxozincate(II).

Note: IUPAC nomenclature for the coordination compound is different depending upon the type of coordination compound it is. The various type of coordination compound formed are cationic coordination compound, anionic coordination compound neutral coordination compound etc. the coordination compound entity has different nomenclature varying on the presence of central atom and the ligand attached to it