Net Ionic Equation Calculator
Pick a reaction to see its molecular equation, the complete (total) ionic equation, and the net ionic equation with the spectator ions identified — the same three-step method taught in class.
Example: with Reaction HCl + NaOH (strong acid + strong base) · State symbols Show (aq), (s), (l), (g) → Net ionic equation: H⁺(aq) + OH⁻(aq) → H2O(l).
Computed by the calculator below using its default values. Change any input to see your own numbers.
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Check it outHow to write a net ionic equation
Every net ionic equation comes from the same three steps. 1) Write the balanced molecular equation. 2) Split every strong electrolyte — soluble ionic compounds, strong acids, strong bases — into its dissolved ions; that is the complete (total) ionic equation. 3) Cancel the spectator ions that appear unchanged on both sides. What survives is the net ionic equation. For AgNO₃ + NaCl, silver and chloride are the only ions that change: Ag⁺(aq) + Cl⁻(aq) → AgCl(s), while Na⁺ and NO₃⁻ just watch. Solids, liquids, gases, and weak electrolytes (like CH₃COOH, NH₃, and water) never get split.
Solubility rules, condensed
- Always soluble: salts of Na⁺, K⁺, NH₄⁺, and all nitrates and acetates — these ions are the usual spectators.
- Chlorides, bromides, iodides are soluble except with Ag⁺, Pb²⁺, and Hg₂²⁺; sulfates are soluble except with Ba²⁺, Sr²⁺, Pb²⁺ (Ca²⁺ is borderline).
- Carbonates, phosphates, hydroxides, and sulfides are mostly insoluble — expect a precipitate unless the cation is from the first rule.
How it’s calculated
Each preset stores a balanced molecular equation. Strong electrolytes — soluble salts per standard solubility rules, strong acids (HCl, H2SO4), and strong bases (NaOH, KOH) — are dissociated into aqueous ions to form the complete ionic equation. Ions identical on both sides (spectators) are removed and the remaining coefficients reduced to lowest terms, giving the net ionic equation. Solids, liquids, gases, and weak electrolytes (CH3COOH, NH3, H2O) stay undissociated throughout.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Splitting everything into ions — solids, liquids, gases, and weak acids or bases stay written whole; only dissolved strong electrolytes dissociate.
- Forgetting to reduce coefficients: H2SO4 + 2 NaOH first gives 2 H⁺ + 2 OH⁻ → 2 H2O, which simplifies to H⁺ + OH⁻ → H2O.
- Balancing atoms but not charge — a correct net ionic equation balances both (Zn + 2 H⁺ → Zn²⁺ + H₂ carries +2 on each side).
Frequently asked questions
What is a net ionic equation?
An equation showing only the species that actually change during a reaction — the ions that form a precipitate, gas, or weak electrolyte. Spectator ions, which stay dissolved and unchanged, are removed.
What is the difference between complete ionic and net ionic equations?
The complete (total) ionic equation shows every dissolved strong electrolyte split into ions, spectators included. The net ionic equation is what remains after identical ions on both sides are canceled.
How do I find the spectator ions?
Dissociate the strong electrolytes on each side, then look for ions that appear identically in reactants and products. In AgNO₃ + NaCl, Na⁺ and NO₃⁻ are the spectators.
What if every ion cancels out?
Then there is no reaction. Mixing NaCl and KNO₃ gives four soluble, unchanged ions and no precipitate, gas, or weak electrolyte — so no net ionic equation exists.
Why is water written as H2O and not split into ions?
Water is a very weak electrolyte — only about one molecule in half a billion is ionized at 25°C — so it stays molecular, written H2O(l).