Question

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

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

Hint:

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

Answer 1

The Correct Option is C

Concept: In coordination compounds, the oxidation state of the central metal ion can be determined using the charges of ligands and the overall charge of the complex. Important points: \begin{itemize} \item \(NH_3\) is a neutral ligand. \item \(Cl^{-}\) carries a charge of \(-1\). \item The compound \([Co(NH_3)_6]Cl_3\) contains three chloride ions outside the coordination sphere. \end{itemize} Step 1: {\color{red}Determine the charge on the complex ion.} Since there are \(3\) chloride ions \((Cl^-)\), the complex ion must have a charge of: \[ [Co(NH_3)_6]^{3+} \] Step 2: {\color{red}Let the oxidation state of cobalt be \(x\).} \[ x + 6(0) = +3 \] Step 3: {\color{red}Solve the equation.} \[ x = +3 \] Thus, the oxidation state of cobalt is: \[ \boxed{+3} \] \bigskip