Question

The IUPAC name of [Co(NH₃)₅(CO₃)]Cl is

• A. Pentaamminecarbonatocobalt (III) Chloride
• B. Carbonatopentamminecobalt (III) Chloride
• C. Pentaamminecarbonatocobaltate (III) Chloride
• D. Pentaammine cobalt (III) Carbonate Chloride

Answer 1

The Correct Option is A

To solve the problem, we need to determine the correct IUPAC name for the coordination compound [Co(NH₃)₅(CO₃)]Cl.

1. Identifying the Components:
The given compound is a coordination complex with the formula [Co(NH₃)₅(CO₃)]Cl. Here: - The central metal ion is cobalt (Co). - The ligands are ammine (NH₃) and carbonate (CO₃^2-). - The counter ion is chloride (Cl^-).

2. Determining the Oxidation State of Cobalt:
Let the oxidation state of cobalt be \( x \). The carbonate ion (CO₃^2-) has a charge of -2, and the ammine ligands (NH₃) are neutral. The overall charge of the complex ion is balanced by one chloride ion (Cl^-), so: \[ x + 5(0) + (-2) = +1 \] \[ x - 2 = +1 \] \[ x = +3 \] Thus, the oxidation state of cobalt is +3, denoted as cobalt(III).

3. Naming the Ligands:
- Ammine (NH₃) is named as pentammine (since there are five NH₃ ligands). - Carbonate (CO₃^2-) is named as carbonato.

4. Order of Ligands in the Name:
Ligands are named in alphabetical order. Here, "ammine" (A) comes before "carbonato" (C). Thus, the order is pentamminecarbonato.

5. Naming the Complex:
The name of the complex cation is constructed as: \[ \text{pentamminecarbonatocobalt(III)} \] Since the complex is a cation, we do not use the suffix "-ate". The chloride ion is named separately as chloride.

6. Final IUPAC Name:
Combining all parts, the IUPAC name is: \[ \text{Pentamminecarbonatocobalt(III) Chloride} \]

7. Matching with the Given Options:
The correct option is: (A) Pentamminecarbonatocobalt (III) Chloride

Final Answer:
The IUPAC name of the compound is \({(A) \text{Pentamminecarbonatocobalt (III) Chloride}}\).

Answer 2

The complex ion [Co(NH₃)₅(CO₃)] is named by first listing the ligands in alphabetical order. "Amine" is named before "carbonate" due to its alphabetical order. The oxidation state of cobalt is (III), and the chloride ion (Cl) is named at the end. Therefore, the correct IUPAC name is Pentaamminecarbonatocobalt(III) Chloride.

The correct answer is (A) : Pentaamminecarbonatocobalt (III) Chloride.