Question

What is the oxidation state of cobalt in \([\text{Co}(\text{NH}_3)_6]^{3+}\) ?

• A. \(+5\)
• B. \(+4\)
• C. \(+3\)
• D. \(+2\)

Hint:

Ammonia is neutral, so the metal carries the full charge of the complex.

Answer 1

The Correct Option is C

Step 1: Quick Rule:
When all ligands are neutral, oxidation state equals the charge on the ion.

Step 2: Apply:
The charge is 3+, so Co is +3. This is the common cobalt(III) hexaammine ion.

Step 3: Answer:
Option (C).

Final Answer:
Option (C). \[ \boxed{\text{(C) } +3} \]