BaCl2 + Na2SO4 → BaSO4 + 2NaCl
Barium chloride and sodium sulfate — balanced chemical equation, step by step.
The white barium sulfate precipitate formed here is the standard test for sulfate ions.
How to balance BaCl2 + Na2SO4 = BaSO4 + NaCl
In a double-replacement reaction, the ions of two compounds swap partners — often forming a precipitate. Balancing means choosing coefficients so that every element has the same number of atoms on both sides of the arrow — the Law of Conservation of Mass. Here is how it's done, step by step.
Step 1 — Write the unbalanced equation
Start with the correct formulas for every reactant and product:
BaCl2 + Na2SO4 = BaSO4 + NaCl
Step 2 — Count the atoms of each element
With no coefficients yet (everything counted once), the atoms do not match. The ✗ marks show which elements are unbalanced:
| Element | Reactants | Products | Equal? |
|---|---|---|---|
| Ba | 1 | 1 | ✓ |
| Cl | 2 | 1 | ✗ |
| Na | 2 | 1 | ✗ |
| S | 1 | 1 | ✓ |
| O | 4 | 4 | ✓ |
Step 3 — Add the smallest whole-number coefficients
Adjust the coefficients in front of each formula until every element balances. The smallest whole-number coefficients are 1 BaCl2, 1 Na2SO4, 1 BaSO4, 2 NaCl, giving:
BaCl2 + Na2SO4 = BaSO4 + 2NaCl
For a double-replacement reaction, treat each polyatomic ion (such as NO₃⁻ or SO₄²⁻) as a single unit and balance those groups before the individual atoms.
Step 4 — Verify the balance
Recount every element. Each one now matches on both sides:
| Element | Reactants | Products | Balanced |
|---|---|---|---|
| Ba | 1 | 1 | ✓ |
| Cl | 2 | 2 | ✓ |
| Na | 2 | 2 | ✓ |
| S | 1 | 1 | ✓ |
| O | 4 | 4 | ✓ |
All elements are balanced and the coefficients are the smallest whole numbers, so BaCl2 + Na2SO4 = BaSO4 + 2NaCl is the correct balanced equation.
Molar masses and mole ratio
The balanced coefficients are also the mole ratio of the reaction. Using standard atomic masses, the molar mass of each substance is:
| Substance | Role | Molar mass (g/mol) | Moles |
|---|---|---|---|
| BaCl2 | reactant | 208.23 | 1 |
| Na2SO4 | reactant | 142.04 | 1 |
| BaSO4 | product | 233.38 | 1 |
| NaCl | product | 58.44 | 2 |
For this reaction the mole ratio is 1 : 1 : 1 : 2. Combine these molar masses with the ratio in the free stoichiometry calculator to convert between moles, grams, and the number of particles for any reactant or product.
Try another equation
Use the free balancer to solve any reaction instantly with step-by-step explanations and a stoichiometry calculator.
Open the balancer →