Question

The IUPAC name of \( K_3[\text{Fe(CN)_6] \) is}

• A. Potassium ferrocyanide
• B. Potassium ferricyanide
• C. Potassium hexacyanoferrate (II)
• D. Potassium hexacyanoferrate (III)

Hint:

In coordination compounds, the prefix "ferro" indicates iron in the +2 oxidation state, while "ferri" indicates iron in the +3 state.

Answer 1

The Correct Option is A

Step 1: Understanding the complex.
In the complex \( K_3[\text{Fe(CN)}_6] \), the iron is in the +2 oxidation state, as indicated by the formula, and it forms a ferrocyanide complex. The term "ferro" refers to the iron in the +2 oxidation state. Step 2: Analysis of options.
(A) Potassium ferrocyanide: Correct — The IUPAC name is Potassium ferrocyanide, which correctly reflects the +2 oxidation state of iron in the complex.
(B) Potassium ferricyanide: This is incorrect because "ferricyanide" refers to the +3 oxidation state of iron.
(C) Potassium hexacyanoferrate (II): This name is incorrect for \( K_3[\text{Fe(CN)}_6] \), which is actually ferrocyanide.
(D) Potassium hexacyanoferrate (III): This name is incorrect because the oxidation state of iron in \( K_3[\text{Fe(CN)}_6] \) is +2, not +3.
Step 3: Conclusion.
The correct answer is (A) because the IUPAC name for \( K_3[\text{Fe(CN)}_6] \) is Potassium ferrocyanide.