Chemical Reactions: Aluminum and Hydrochloric Acid

Chemical Reactions

Reaction of Aluminum with Hydrochloric Acid

When aluminum metal (Al) is placed in an aqueous solution of hydrochloric acid (HCl), a chemical reaction occurs that produces hydrogen gas (H2) and an aqueous solution of aluminum chloride (AlCl3). This is an example of a single displacement (or replacement) reaction, where a metal reacts with an acid to release hydrogen gas.

• Single Displacement Reaction: A type of chemical reaction where one element replaces another in a compound.

• Phases: It is important to indicate the physical states of all reactants and products in the chemical equation.

Balanced Chemical Equation

The balanced chemical equation for this reaction, including phases, is:

$2\,\mathrm{Al}(s) + 6\,\mathrm{HCl}(aq) \rightarrow 2\,\mathrm{AlCl}_3(aq) + 3\,\mathrm{H}_2(g)$

• Al(s): Solid aluminum metal

• HCl(aq): Hydrochloric acid in aqueous solution

• AlCl3(aq): Aluminum chloride dissolved in water

• H2(g): Hydrogen gas released

Key Points

• Aluminum is oxidized: It loses electrons and forms Al3+ ions.

• Hydrogen ions are reduced: They gain electrons and form hydrogen gas.

• Applications: This reaction demonstrates the reactivity of metals with acids and is used in laboratory demonstrations of hydrogen gas production.

Example

If 2 moles of aluminum react with 6 moles of hydrochloric acid, the products will be 2 moles of aluminum chloride and 3 moles of hydrogen gas.