Aluminum is a reactive metal and different grades of aluminum react differently with chemicals especially acids. Certain acid types are harmless to some aluminum grades, while others are harmful.
Acidic solutions can sometimes remove other things from aluminum machine parts without harming the metal, depending on the aluminum grade and acid type.
What Happens When Hydrochloric Acid Is Poured On Aluminum Foil?
Aluminum is a light silvery white metal that effectively reacts with hydrochloric acid at room temperature. The reaction occurs at normal temperature and produces chlorides.
When aluminum reacts with hydrochloric acid, aluminum chloride and hydrogen gas are produced. The reaction is irreversible as the products cannot be converted into reactants again. The balanced equation of this reaction is as follows:
2Al + 6HCl → 2AlCl3 + 3H2↑
What Type Of Reaction Occurs Between Hydrochloric Acid And Aluminum?
A typical single displacement reaction takes place when hydrochloric acid combines with aluminum foil at room temperature. The metal dissolves in hydrochloric acid, yielding aluminum chloride and colorless hydrogen gas.
Dilute acids react with relatively reactive metals such as magnesium, aluminum, and iron. In general, the more reactive the metal, the faster the reaction. In case of aluminum, it reacts slowly with acids because it has a protective oxide layer.
What Is The Mechanism Of Reaction Between Aluminum And Hydrochloric Acid?
An oxidation-reduction process, also known as a redox reaction, occurs when metallic aluminum reacts with hydrochloric acid. Both oxidation and reduction occur concurrently.
Reactions Mechanism
The reaction requires a ratio of two aluminum molecules to six hydrochloric acid molecules because aluminum has three electrons in its outer shell. The reaction starts when each chlorine atom in hydrochloric acid gains an electron from aluminum while losing a hydrogen atom.
Because hydrogen does not like to exist as a single atom, it takes six molecules of hydrochloric acid to make three molecules of the diatomic hydrogen molecule, therefore two molecules of aluminum are needed to keep things balanced.
Listed below are the stepwise reaction taking place in between aluminum and hydrochloric acid
Step 1: Aluminum acts as the reducing agent, giving up electrons:
Al⁰ – 3e → Al³⁺
Step 2: Cations of hydrochloric acid take these electrons and are reduced to molecular hydrogen:
2H⁺ + 2e → H₂↑
The complete ionic reaction equation is as follows:
2Al⁰ + 6H⁺ + 6Cl⁻ → 2Al³⁺ + 6Cl⁻ + 3H₂↑
Net-ionic form:
2Al⁰ + 6H⁺ → 2Al³⁺ + 3H₂↑
In molecular form, the reaction looks as follows:
2Al + 6HCl = 2AlCl₃ + 3H₂↑
Metallic aluminum isn’t the only substance that can react with hydrochloric acid. Many metal compounds have this property. When ions or reactive groups of both reagents “change places,” this is called an exchange reaction.
The reagents must generate a gas, a precipitate, or a poorly soluble substance in order for the reaction with aluminum or its compounds to be irreversible. Precision is required for calculating the required reagent quantities.
What Are The Applications Of Products Formed By The Reaction Of Aluminum And Hydrochloric Acid?
Almost all the products formed as a result of chemical reactions are useful, same is the case with the products formed when aluminum and hydrochloric acid react with each other.
- Aluminum chloride (AlCl3) or its compounds are formed in almost all reactions between hydrochloric acid and aluminum. Organic solvents (nitrobenzene, dichloroethane, acetone) and water readily dissolve the salt. The hydrolysis of AlCl3 can be observed in aqueous solutions, as this salt is produced by the strong acid HCl and the weak base Al(OH)3.
- In organic synthesis, AlCl3 is utilized as a catalyst. It is used in the isomerization of paraffins, the initiation of alkylation reactions, acylation, and the fraction of oil.
- The aluminum chloride hexahydrate AlCl36H2O is used to cure timber materials, purify wastewater, and manufacture antiperspirants.
- The reaction of aluminum with a solution of hydrochloric acid can be utilized as a laboratory method for obtaining hydrogen (although metallic zinc is more commonly used for these purposes).
How To Protect Aluminum From Acid Damage?
Aluminum parts in motors, drives, and gears have been reported to be damaged by hydrochloric and sulfuric acids. Dilution can help to lessen the effects of hydrochloric acid and prevent these parts from acidic damage.
If kept at ambient temperature, very dilute sulfuric acid solutions will not harm aluminum parts. Boric, carbonic, lactic, and nitric acids do not commonly cause aluminum to corrode. Depending on the concentration of the acidic solution and the temperature, chromic acids inflict significant damage.
Related Questions
Why does aluminum not react with hydrochloric acid?
Aluminum does react with hydrochloric acid. When aluminum is poured into an acid, it may appear that it does not react at first. This is because, as a result of the preceding interaction with the air, a coating of aluminum oxide forms on the surface of the aluminum, which acts as a protective barrier. As aluminum chloride forms, the hydrochloric acid quickly turns a dismal grey color.
Does acid affect aluminum?
Aluminum is a flexible, light, silvery-white metal with a high melting point. It’s a good conductor of electricity. It has the ability to react with both acids and bases. When aluminum is combined with an acid, a classic single displacement reaction occurs, resulting in aluminum salt and gaseous hydrogen.
What is the aluminum foil’s coating?
Aluminum foil is usually covered with lacquer or water-based latex or bonded to a polymer film with adhesive or extrusion coating or lamination. Many lidding applications use vinyl-based lacquer-coated aluminum foils, particularly for dairy goods like yogurt.
Conclusion
Aluminum being a metal is reactive towards acids, but due to the presence of protective oxide layer, it is somewhat resistant to acids. However, the above-mentioned reactions show the formation of aluminum chloride which is a useful chemical substance.