Answer
🧪 Net Ionic Equation: NiCO₃ + HI
Question
What is the net ionic equation for the formation of Ni²⁺ and evolution of CO₂ when NiCO₃(s) is mixed with aqueous HI?
Step-by-Step Analysis
1. Full Molecular Equation
NiCO₃(s) + 2HI(aq) → NiI₂(aq) + CO₂(g) + H₂O(l)2. Full Ionic Equation
NiCO₃(s) + 2H⁺(aq) + 2I⁻(aq) → Ni²⁺(aq) + 2I⁻(aq) + CO₂(g) + H₂O(l)3. Cancel Spectator Ions
I⁻ appears on both sides and is a spectator ion, so remove it.
✅ Net Ionic Equation
NiCO₃(s) + 2H⁺(aq) → Ni²⁺(aq) + CO₂(g) + H₂O(l)
Why Other Options Are Incorrect
| Option | Issue |
|---|---|
| 2NiCO₃(s) + HI(aq) → … | Incorrect stoichiometry and improper HI usage |
| NiCO₃(s) + I⁻(aq) → … | I⁻ is not an acid; won’t produce CO₂ |
| NiCO₃(s) + 2HI(aq) → NiI₂(aq) + CO₂ + H₂O | Molecular, not ionic or net ionic |
| NiCO₃(s) + 2HI(aq) → H₂O + CO₂ + Ni²⁺ + 2I⁻ | Full ionic, not net ionic |
Key Concept Recap
- Acids + Carbonates → CO₂ + H₂O + dissolved metal ion
NiCO₃reacts with2H⁺to produceNi²⁺,CO₂(g), andH₂O(l)I⁻is a spectator ion and does not appear in the net ionic equation