When sodium sulphate solution reacts with barium chloride solution, a chemical reaction occurs that produces an insoluble solid called barium sulphate and a solution of sodium chloride.
The Reaction Explained
This specific interaction is a classic example of a double displacement reaction, sometimes referred to as a precipitation reaction because it forms an insoluble solid (a precipitate). It happens when the positive and negative ions of two dissolved ionic compounds switch places.
Reactants and Products
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Reactants:
- Sodium Sulphate (Na₂SO₄): A soluble salt that dissociates into sodium ions (Na⁺) and sulphate ions (SO₄²⁻) in water.
- Barium Chloride (BaCl₂): Another soluble salt that dissociates into barium ions (Ba²⁺) and chloride ions (Cl⁻) in water.
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Products:
- Barium Sulphate (BaSO₄): A compound that is insoluble in water. It forms a white solid that appears cloudy in the solution and eventually settles down.
- Sodium Chloride (NaCl): Common table salt, which is soluble in water and remains dissolved in the solution.
The Process
When solutions of sodium sulphate and barium chloride are mixed:
- The ions from both compounds are free to move around in the water.
- The barium ions (Ba²⁺) encounter the sulphate ions (SO₄²⁻).
- Because barium sulphate is highly insoluble, these ions combine to form solid BaSO₄, which precipitates out of the solution.
- The remaining sodium ions (Na⁺) and chloride ions (Cl⁻) stay in the solution as dissolved sodium chloride.
The overall chemical equation representing this reaction is:
Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s) + 2NaCl(aq)
(aq) denotes an aqueous solution (dissolved in water), and (s) denotes a solid.
Practical Significance
This reaction is widely used in chemistry for several purposes:
- Testing for Sulphate Ions: It's a standard laboratory test. If you add barium chloride solution to an unknown solution and a white precipitate forms, it indicates the presence of sulphate ions.
- Testing for Barium Ions: Similarly, adding sodium sulphate solution can test for the presence of barium ions.
- Gravimetric Analysis: The precipitate of barium sulphate can be filtered, dried, and weighed to determine the amount of sulphate or barium originally present in a sample.
Summary Table
| Reactant 1 | Reactant 2 | Product 1 | Product 2 | Key Observation |
|---|---|---|---|---|
| Sodium Sulphate | Barium Chloride | Barium Sulphate | Sodium Chloride | Formation of a white, insoluble solid (precipitate). |
| (Soluble Salt) | (Soluble Salt) | (Insoluble Solid) | (Soluble Salt) |
The reaction between sodium sulphate solution and barium chloride solution results in the formation of an insoluble white precipitate, barium sulphate, and a soluble solution of sodium chloride. This is a clear demonstration of a double displacement reaction where ion exchange leads to the formation of an insoluble product.
