Question

Oxidation state of central metal atom in the given complex is: \[ [Co(NH_3)_4(H_2O)_2]Cl_3 \]

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

Hint:

For coordination complexes, neutral ligands don’t affect the oxidation state calculation. Only the counter ions matter.

Answer 1

The Correct Option is B

Step 1: Let the oxidation state of Co be \( x \).
\[ 4(NH_3) + 2(H_2O) + Co + 3Cl^- = 0 \] Step 2: \( NH_3 \) and \( H_2O \) are neutral ligands, so they contribute zero charge.
Chloride ion has a charge of \( -1 \) each. Total charge of three Cl\(^-\) is \(-3\).
\[ x + 0 - 3 = 0 \quad \Longrightarrow \quad x = +3 \]