Write a balanced net ionic equation for dissolution reaction of Fe(OH)3Fe(OH)3.
The correct answer and explanation is:
✅ Balanced Net Ionic Equation for the Dissolution of Fe(OH)₃:
Fe(OH)3(s)⇌Fe3+(aq)+3OH−(aq)\text{Fe(OH)}_3 (s) \rightleftharpoons \text{Fe}^{3+} (aq) + 3\text{OH}^- (aq)
🧪 Explanation (300 Words):
The dissolution of iron(III) hydroxide, Fe(OH)₃, in water is an example of a chemical equilibrium involving a slightly soluble ionic compound. The net ionic equation focuses only on the ions and species that undergo change, omitting spectator ions or molecular forms not directly involved in the process.
⚙️ Step-by-Step Breakdown:
- Chemical Nature:
Fe(OH)₃ is a sparingly soluble base, meaning it only dissolves to a small extent in water. When it does dissolve, it dissociates into iron(III) ions (Fe³⁺) and hydroxide ions (OH⁻). - Dissolution Reaction:
The solid Fe(OH)₃ dissociates into its ions: Fe(OH)3(s)→Fe3+(aq)+3OH−(aq)\text{Fe(OH)}_3 (s) \rightarrow \text{Fe}^{3+} (aq) + 3\text{OH}^- (aq) - Net Ionic Equation:
Since Fe(OH)₃ is a solid, and the products are aqueous ions, this reaction is already in net ionic form. No spectator ions are involved. - Balancing:
- One Fe atom on both sides.
- Three OH⁻ groups dissociate, producing 3 moles of hydroxide ions.
- Charges are balanced:
LHS: neutral solid
RHS: +3 from Fe³⁺ and −3 from 3 OH⁻ = net charge 0 ✅
🧬 Significance in Chemistry:
This dissolution equation is essential in understanding solubility equilibria, particularly in acid-base reactions, precipitation, and environmental chemistry. For instance, in acidic conditions, the hydroxide ions are neutralized by H⁺, shifting the equilibrium and increasing Fe(OH)₃ solubility (Le Chatelier’s Principle).
🔍 Summary:
- Net Ionic Equation: Fe(OH)3(s)⇌Fe3+(aq)+3OH−(aq)\text{Fe(OH)}_3 (s) \rightleftharpoons \text{Fe}^{3+} (aq) + 3\text{OH}^- (aq)
- This reflects the equilibrium between the solid and its dissociated ions in water.