Choose the correct balanced chemical equation for the ionic dissociation of aluminum sulfate, Al2(SO4)3, in water: Al2(SO4)3 (aq) → 2 Al3+ (aq) + 3 SO4^2- (aq)
The Correct Answer and Explanation is:
The correct balanced chemical equation for the ionic dissociation of aluminum sulfate in water is:
Al2(SO4)3 (aq) → 2 Al³⁺ (aq) + 3 SO₄²⁻ (aq)
Explanation:
Aluminum sulfate, Al₂(SO₄)₃, is an ionic compound that dissociates into its constituent ions when it dissolves in water. This dissociation occurs because the ionic bonds between aluminum ions (Al³⁺) and sulfate ions (SO₄²⁻) are broken in the presence of water due to the strong electrostatic interactions between the ions and the water molecules.
- Aluminum sulfate consists of two aluminum ions (Al³⁺) for every three sulfate ions (SO₄²⁻).
- When it dissolves in water, these ions separate due to their opposite charges attracting the water molecules, which surround and stabilize the individual ions.
The process can be visualized in steps:
- Aluminum sulfate dissociates: The formula unit of Al₂(SO₄)₃, which contains two aluminum ions and three sulfate ions, breaks apart into these ions when the solid dissolves in water.
- Ionic dissociation: The two Al³⁺ ions are released into the solution, while the three SO₄²⁻ ions are also released.
- Balanced equation: The balanced equation ensures that the number of each type of ion on both sides of the equation is the same:
- 2 Al³⁺ ions
- 3 SO₄²⁻ ions
The coefficient “2” in front of Al³⁺ and “3” in front of SO₄²⁻ ensures that the total charge and number of atoms are conserved. Therefore, the correct dissociation equation is Al₂(SO₄)₃ (aq) → 2 Al³⁺ (aq) + 3 SO₄²⁻ (aq).
