When sodium sulfate (Na₂SO₄) dissolves in water, it dissociates into its constituent ions.
Sodium sulfate (Na₂SO₄) is an ionic compound. When placed in water, which is a polar solvent, the positive ends of water molecules attract the negative ions in sodium sulfate, and the negative ends of water molecules attract the positive ions. This interaction causes the ionic lattice structure of sodium sulfate to break apart, releasing the individual ions into the solution. This process is called dissociation.
The Dissociation Process
Sodium sulfate dissociates into sodium ions and sulfate ions.
- Sodium (Na) is a metal from Group 1, forming a positive ion with a charge of +1 (Na⁺).
- Sulfate (SO₄) is a group of nonmetals (sulfur and oxygen) bonded together that carries an overall negative charge. As mentioned in the reference, this group is a polyatomic ion called the sulfate ion, with a charge of -2 (SO₄²⁻).
The chemical formula Na₂SO₄ indicates that for every one sulfate ion (SO₄²⁻) with a -2 charge, there are two sodium ions (Na⁺) each with a +1 charge, balancing the overall charge (2 +1 + 1 -2 = 0).
The Dissociation Equation
The dissociation of solid sodium sulfate (Na₂SO₄(s)) in water results in aqueous sodium ions (Na⁺(aq)) and aqueous sulfate ions (SO₄²⁻(aq)). The balanced chemical equation representing this dissociation is:
Na₂SO₄(s) → 2Na⁺(aq) + SO₄²⁻(aq)
This equation shows that one formula unit of sodium sulfate yields two sodium ions and one sulfate ion when it dissociates in water.
Summary of Ions Produced
| Ion Name | Chemical Formula | Charge | Number of Ions per Na₂SO₄ Formula Unit |
|---|---|---|---|
| Sodium Ion | Na⁺ | +1 | 2 |
| Sulfate Ion | SO₄²⁻ | -2 | 1 |
Understanding how ionic compounds like sodium sulfate dissociate is fundamental in chemistry, particularly when studying solutions, solubility, and chemical reactions in aqueous environments.
