# What net ionic equation do I get?

Balances a reaction in water, writes the complete ionic equation from the solubility rules and strong acids, and cancels the spectator ions to give the net ionic equation.

- Page: https://www.acalculator.org/chemistry/net-ionic-equation-calculator
- JSON spec: https://www.acalculator.org/chemistry/net-ionic-equation-calculator.json
- Version: 9fc922782502

## Default answer

Example with the default inputs (Molecular equation AgNO3 + NaCl = AgCl + NaNO3): The net ionic equation is Ag⁺(aq) + Cl⁻(aq) → AgCl(s).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| eq | Molecular equation | The reaction in water: formulas joined by +, with = or → between reactants and products. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| net | Net ionic equation | The complete ionic equation with the spectator ions taken out, in lowest whole numbers. |
| molecular | Balanced molecular equation | The balanced equation with the states the page used. |
| complete | Complete ionic equation | Every strong electrolyte in water written as its ions. |
| spectators | Spectator ions | Ions that appear unchanged on both sides. |

## Method

Balance the molecular equation; write each soluble ionic compound (Table 4.1), each strong acid (Table 4.2) and each ion in water as its ions; cancel ions found unchanged on both sides; divide by the common factor.

## Assumptions

- Reactions in water at room temperature. Solubility follows OpenStax Chemistry 2e Table 4.1; a state you type, (aq), (s), (l) or (g), overrides it.
- Strong acids: HCl, HBr, HI, HNO₃, HClO₄ and H₂SO₄ (both protons). Every other molecule, including weak acids, water and gases, stays whole; water with no state typed is shown as H₂O(l).
- Ionic hydroxides that Table 4.1 calls soluble (group 1 and Ba(OH)₂) are strong bases.

## Worked examples

1. eq = NaCl(aq) + AgNO3(aq) = AgCl(s) + NaNO3(aq) gives net = Cl⁻(aq) + Ag⁺(aq) → AgCl(s), spectators = Na⁺(aq), NO₃⁻(aq). Source: OpenStax, Chemistry 2e, §4.2 Classifying Chemical Reactions (NaCl(aq) + AgNO₃(aq) ⟶ AgCl(s) + NaNO₃(aq); net ionic Ag⁺(aq) + Cl⁻(aq) ⟶ AgCl(s)). https://openstax.org/books/chemistry-2e/pages/4-2-classifying-chemical-reactions.
2. eq = Ba(OH)2 + HNO3 = Ba(NO3)2 + H2O gives molecular = Ba(OH)₂(aq) + 2HNO₃(aq) → Ba(NO₃)₂(aq) + 2H₂O(l), net = OH⁻(aq) + H⁺(aq) → H₂O(l). Source: OpenStax, Chemistry 2e, §4.2 Classifying Chemical Reactions, Example 4.4 (Ba(OH)₂(aq) + 2HNO₃(aq) ⟶ Ba(NO₃)₂(aq) + 2H₂O(l); strong acids in Table 4.2; ionic hydroxides are strong bases). https://openstax.org/books/chemistry-2e/pages/4-2-classifying-chemical-reactions.
3. eq = CaCl2 + Na3PO4 = Ca3(PO4)2 + NaCl gives molecular = 3CaCl₂(aq) + 2Na₃PO₄(aq) → Ca₃(PO₄)₂(s) + 6NaCl(aq), net = 3Ca²⁺(aq) + 2PO₄³⁻(aq) → Ca₃(PO₄)₂(s), spectators = Cl⁻(aq), Na⁺(aq). Source: OpenStax, Chemistry 2e, §4.2, Table 4.1 (chlorides and group 1 compounds are soluble; phosphates are insoluble except with group 1 and NH₄⁺). https://openstax.org/books/chemistry-2e/pages/4-2-classifying-chemical-reactions.
4. eq = HC2H3O2 + NaOH = NaC2H3O2 + H2O gives net = HC₂H₃O₂ + OH⁻(aq) → C₂H₃O₂⁻(aq) + H₂O(l), spectators = Na⁺(aq). Source: OpenStax, Chemistry 2e, §4.2 (acetic acid is a weak acid: about 1% ionized; sodium compounds and acetates are soluble). https://openstax.org/books/chemistry-2e/pages/4-2-classifying-chemical-reactions.

## FAQ

### How do I write a net ionic equation?

Balance the molecular equation. Write every soluble ionic compound and strong acid in water as its ions (the complete ionic equation). Cross out ions that appear unchanged on both sides, the spectators, and reduce the coefficients. For NaCl(aq) + AgNO₃(aq) → AgCl(s) + NaNO₃(aq), the net ionic equation is Ag⁺(aq) + Cl⁻(aq) → AgCl(s).

### What are spectator ions?

Ions that are in the solution before and after the reaction without changing, such as Na⁺ and NO₃⁻ when silver chloride precipitates. They balance the charge but take no part in the reaction, so the net ionic equation leaves them out.

### Which compounds are split into ions?

Soluble ionic compounds (by the solubility rules), the strong acids HCl, HBr, HI, HNO₃, HClO₄ and H₂SO₄, and ions you type. Solids, water, gases and weak acids such as acetic acid stay whole.

### How do I know if a compound is soluble?

The page uses OpenStax Chemistry 2e Table 4.1. Compounds of NH₄⁺ and group 1 cations are soluble; so are acetates, nitrates, chlorates and hydrogen carbonates. Chlorides, bromides and iodides are soluble except with Ag⁺, Hg₂²⁺ and Pb²⁺. Carbonates, chromates, phosphates and sulfides are insoluble except with group 1 and NH₄⁺. Hydroxides are insoluble except with group 1 and Ba²⁺.

### What is the net ionic equation for a strong acid and a strong base?

H⁺(aq) + OH⁻(aq) → H₂O(l). For HCl + NaOH, Na⁺ and Cl⁻ are spectators. OpenStax writes the acid ion as H₃O⁺, which is the same reaction.

### What if every ion is a spectator?

Then no precipitate, water, gas or weak electrolyte forms, and there is no reaction. Mixing NaCl and KNO₃ solutions just gives a solution of four ions, so the page shows no net ionic equation.

### Can I type the states myself?

Yes. Add (aq), (s), (l) or (g) after a formula, as in AgCl(s). A typed state overrides the solubility rules: (aq) splits an ionic compound or strong acid into ions; (s), (l) and (g) keep the formula whole.

## Sources

- OpenStax, Chemistry 2e, §4.2 Classifying Chemical Reactions (Table 4.1 Solubilities of Common Ionic Compounds in Water; Table 4.2 Common Strong Acids; the AgCl net ionic equation; Example 4.4). https://openstax.org/books/chemistry-2e/pages/4-2-classifying-chemical-reactions (retrieved 2026-10-01)
- OpenStax, Chemistry 2e, §4.1 Writing and Balancing Chemical Equations (molecular, complete ionic and net ionic equations). https://openstax.org/books/chemistry-2e/pages/4-1-writing-and-balancing-chemical-equations (retrieved 2026-10-01)