The number of ions formed from a molecule of potassium ferrocyanide in aqueous solution is — Coordination Compounds Chemistry Question

💡 Solution & Explanation

I need to determine how many ions are formed when potassium ferrocyanide dissolves in aqueous solution. **Step 1: Identify the formula of potassium ferrocyanide** Potassium ferrocyanide is $K_4[Fe(CN)_6]$ **Step 2: Determine complete dissociation in aqueous solution** When $K_4[Fe(CN)_6]$ dissolves in water, it completely dissociates into its ionic components: $$K_4[Fe(CN)_6] \rightarrow 4K^+ + [Fe(CN)_6]^{4-}$$ **Step 3: Check if the complex ion further dissociates** The ferrocyanide complex ion $[Fe(CN)_6]^{4-}$ is a stable coordination complex with very strong metal-ligand bonds. In aqueous solution, it does **not dissociate** into $Fe^{2+}$ and $CN^-$ ions under normal conditions due to the high stability constant of this complex. **Step 4: Count total ions** From one molecule of $K_4[Fe(CN)_6]$: - 4 potassium ions: $K^+$ - 1 ferrocyanide complex ion: $[Fe(CN)_6]^{4-}$ **Total number of ions = 4 + 1 = 5 ions** The answer is **C** (which corresponds to **5 ions**).