Question

The IUPAC name of complex compound [Co(NH$_3$)$_6$]Cl$_3$ is

• A. Hexa-ammine cobalt (III) chloride
• B. Hexa-ammine cobalt (II) chloride
• C. Hexa-ammine trichloridocobalt (III)
• D. None of these

Hint:

When naming coordination compounds, remember to list the ligands first, followed by the metal and its oxidation state in parentheses, and finish with the counterions.

Answer 1

The Correct Option is A

Step 1: Understand the naming convention for coordination compounds.
The IUPAC name of a coordination compound follows the format: \[ \text{Ligand names} + \text{Metal name} + \text{Oxidation state of metal} + \text{Counterion}. \] For the complex [Co(NH$_3$)$_6$]Cl$_3$, the ligands are NH$_3$ (ammine), cobalt (Co) is the metal, and the oxidation state of cobalt is +3 (since the complex is neutral and the chloride ions are -1 each).
Step 2: Apply the IUPAC naming conventions.
- The complex contains 6 NH$_3$ ligands, which are called "ammine". - The oxidation state of cobalt is +3, so it is named "cobalt (III)". - The counterion is chloride (Cl), which is written as "chloride" at the end.
Step 3: Apply to the options.
The correct IUPAC name for the compound [Co(NH$_3$)$_6$]Cl$_3$ is "Hexa-ammine cobalt (III) chloride".
Final Answer: \[ \boxed{\text{Hexa-ammine cobalt (III) chloride}} \]