Question

What is the oxidation state of Cobalt in \([Co(NH_3)_6]Cl_3\)?

• A. \(+1\)
• B. \(+2\)
• C. \(+3\)
• D. \(+4\)

Hint:

Neutral ligands such as \(NH_3\), \(H_2O\), and \(CO\) contribute zero charge. Only charged ligands affect the oxidation state calculation.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The objective is to find the formal charge on the central Cobalt (\(Co\)) atom in a coordination complex.
Step 2: Key Formula or Approach:
The sum of the oxidation states of all atoms in a neutral compound equals zero.
Oxidation State of Metal + (Number of ligands \(\times\) Charge of ligand) + (Number of counter ions \(\times\) Charge of ion) = \(0\).
Step 3: Detailed Explanation:
In \([Co(NH_3)_6]Cl_3\):
- \(NH_3\) is a neutral molecule, so its charge is \(0\).
- \(Cl\) as a chloride ion has a charge of \(-1\). There are three \(Cl^-\) ions.
Let the oxidation state of \(Co\) be \(x\).
\[ x + 6(0) + 3(-1) = 0 \]
\[ x + 0 - 3 = 0 \]
\[ x = +3 \]
Step 4: Final Answer:
The oxidation state of Cobalt is \(+3\).