Hydrochloric acid dissolves solid aluminum hydroxide. What is the net ionic equation of this reaction? Select the correct answer below: 3 HCI + Al(OH)3 ? 3 H2O + AICI3 3 H+(aq) + 3 Cl?(aq) + Al(OH)3(s) ? 3 H2O(l) + Al³?(aq) + 3 Cl?(aq) 3 H+(aq) + Al(OH)3(s) ? 3 H2O(l) + Al³?(aq) 3 H+(aq) + 3 Cl?(aq) + Al(OH)3(s) ? 3 H2O(l) + Al³?(aq)
The Correct Answer and Explanation is:
Correct Answer:
3 H⁺(aq) + Al(OH)₃(s) → 3 H₂O(l) + Al³⁺(aq)
Explanation:
When hydrochloric acid (HCl) reacts with aluminum hydroxide (Al(OH)₃), a neutralization reaction occurs. This type of reaction involves the combination of hydrogen ions (H⁺) from the acid with hydroxide ions (OH⁻) from the base to produce water (H₂O). In addition to water, a salt — in this case, aluminum chloride (AlCl₃) — is formed.
To understand the net ionic equation, it is important to remove spectator ions. Spectator ions are those that do not participate directly in the chemical transformation but appear unchanged on both sides of the complete ionic equation.
First, write the full molecular equation:
Al(OH)₃(s) + 3 HCl(aq) → AlCl₃(aq) + 3 H₂O(l)
Now, break all the soluble strong electrolytes (like HCl and AlCl₃) into their respective ions:
Al(OH)₃(s) + 3 H⁺(aq) + 3 Cl⁻(aq) → Al³⁺(aq) + 3 Cl⁻(aq) + 3 H₂O(l)
In this equation, the chloride ions (Cl⁻) appear on both sides without change. They are spectator ions and can be eliminated from the net ionic equation. The net ionic equation focuses only on the species that undergo a chemical change.
Net Ionic Equation:
3 H⁺(aq) + Al(OH)₃(s) → 3 H₂O(l) + Al³⁺(aq)
This equation clearly shows the neutralization of hydroxide ions by hydrogen ions to form water, and the dissolution of aluminum hydroxide into aluminum ions in solution. It emphasizes the acid-base nature of the reaction, with H⁺ ions neutralizing the OH⁻ groups in Al(OH)₃.
