The formula of the complex tris (ethylenediamine) cobalt (III) sulphate is
Answer & explanation
Correct answer: option 3
The correct formula of the complex tris (ethylenediamine) cobalt (III) sulphate is (3) [Co(en)3]2(SO4)3.
The complex has a central cobalt atom with a coordination number of 6. It is bonded to three ethylenediamine ligands and three sulfate ligands. The oxidation state of the cobalt atom is +3.
The formula for the complex follows the following rules:
- The ligands are named in alphabetical order, regardless of their charge.
- The name of the central atom is followed by its oxidation state in parentheses.
- The ligands are named in their uncharged form, with the suffix "o" added if they are negatively charged.
- If the complex contains more than one of the same ligand, the number of ligands is indicated by a prefix. For example, two chloride ligands would be named "dichloro".
Therefore, the formula of the complex is [Co(en)3]2(SO4)3. The other options are incorrect because they do not follow the IUPAC naming conventions.