Aluminium: Reactions with Acids and Alkalies
Focuses on the characteristic reactions of aluminium with both acidic and alkaline solutions.
What is Aluminium: Reactions with Acids and Alkalies?
A substance that can react as both an acid and a base.
Key formula / rule: Reaction with Hydrochloric Acid
Key points
- To understand the amphoteric nature of aluminium.
- To write balanced chemical equations for reactions of aluminium with acids and alkalis.
- To identify the products formed in these reactions.
- To explain the role of the oxide layer in aluminium's reactivity.
Common exam trap
Forgetting that aluminium reacts with strong alkalis.
Definitions
- Term
Amphoteric
- Meaning
A substance that can react as both an acid and a base.
- Term
Aluminate
- Meaning
A compound containing the [Al(OH)₄]⁻ anion or related species.
- Term
Passivation
- Meaning
The formation of a protective oxide layer on a metal surface, reducing its reactivity.
Learning objectives
To understand the amphoteric nature of aluminium.
To write balanced chemical equations for reactions of aluminium with acids and alkalis.
To identify the products formed in these reactions.
To explain the role of the oxide layer in aluminium's reactivity.
Formulae
- Name
Reaction with Hydrochloric Acid
- Note
Forms aluminium chloride and hydrogen gas.
- Expression
2Al(s) + 6HCl(aq) → 2AlCl₃(aq) + 3H₂(g)
- Name
Reaction with Sodium Hydroxide
- Note
Forms sodium tetrahydroxoaluminate(III) and hydrogen gas.
- Expression
2Al(s) + 2NaOH(aq) + 6H₂O(l) → 2Na[Al(OH)₄](aq) + 3H₂(g)
Prerequisites
Understanding of acids and bases.
Knowledge of chemical reaction equations.
Concept of amphoteric substances.
Properties of Group 13 elements.
Common mistakes
Forgetting that aluminium reacts with strong alkalis.
Confusing the products formed in acidic and alkaline reactions.
Underestimating the reactivity of aluminium due to its protective oxide layer.
Keywords
Aluminium
Amphoteric
Acids
Alkalies
Hydrogen gas
Aluminium oxide
Aluminates
Group 13 Elements
Practice preview
When aluminium reacts with sodium hydroxide solution, the products formed are:…
easy
Which of the following statements is INCORRECT regarding the reaction of Aluminium with acids and alkalies?…
easy
Which of the following acids will NOT react with aluminium metal at room temperature?…
medium