Question

Identify the oxidation state of chromium in \( \text{K}_3[\text{Cr}(\text{C}_2\text{O}_4)_3] \).

• A. \(+3\)
• B. \(+2\)
• C. \(+6\)
• D. \(+5\)

Hint:

Sum of oxidation states in a complex equals the charge on the complex ion.

Answer 1

The Correct Option is A

Step 1: Determine the charge on the complex ion.
Since there are three \(\text{K}^+\) ions, the charge on the complex ion is \(-3\).
Step 2: Assign charges to ligands.
Each oxalate ion \((\text{C}_2\text{O}_4)^{2-}\) has a charge of \(-2\). Total charge from ligands \(= 3 \times (-2) = -6\).
Step 3: Calculate oxidation state of chromium.
Let oxidation state of Cr be \(x\): \[ x - 6 = -3 \Rightarrow x = +3 \] Step 4: Conclusion.
The oxidation state of chromium is \(+3\).