A prominent "group 13" element, which is also a member of the Boron family whose electronic configuration is 1s2 2s2 2p6 3s2 3p1 is known as Aluminium. The addition of the first three Ionization enthalpies of the Aluminium, AI3+ ions can form. It usually furnishes +3 oxidation states and also is a high electropositive element which is in the case of Aluminium Oxide (Al2O3). The other type of oxidation states is +2 and +1. A transparent Aluminium oxide (Al2O3) layer protects it which forms in the air. There are physical and chemical properties of Aluminium, and its uses can also be seen.
Three Properties Of Aluminium
To explain what are the properties of Aluminium, the 3 properties of Aluminium can be described as follows:
The first of the three chemical properties of Aluminium is the Reaction of Aluminium with air. Aluminium metal generally does not react with air as the surface of it is covered with an oxide layer which protects the coating from the attack of air. If the oxide layer gets damaged, the exposure of the Aluminium metal can be seen which reacts with oxygen and helps in the formation of amphoteric oxide (Aluminium (III) Oxide), Al2O3.
4Al (s) + 3O2 (l) → 2Al2O3 (s)
The second of the three chemical properties of Aluminium is the reaction of Aluminium with acids. Mineral acids react with Aluminium to make solutions which contain liquid AI (III) ion along with the release of hydrogen gas, H2. The reaction of Aluminium with HCl releases hydrogen gas.
2Al3+ (aq) +6HCl (aq) → 3H2 (g) + 6Cl– (aq)
This is how the reaction of Aluminium with hydrochloric acid happens.
The third of the three chemical properties of Aluminium is the reaction of Aluminium with alkalis. This reaction leads to the liberation of hydrogen gas (H2). Oxygen and Aluminium electronegativity make it possible for the Aluminium to form covalent bonds along with oxygen if Aluminium reacts with warm, sodium hydroxide solution to create a colourless solution of sodium tetrahydroxoaluminate along with the release of hydrogen gas.
2Na+ (aq) + 2[Al (OH)4]– + 3H2 (g) → 2Al (s) + 2NaOH (aq) + 6H2O
Other than the three properties of Aluminium which are chemical properties of Aluminium, there are few physical properties of Aluminium.
The 3 properties of Aluminium Which are Physical Properties, Can Be Explained:
Aluminium is a silver type of metal with a tint that is bluish.
The melting point is 660°C (1,220°F), and the boiling point is 2,327-2,450°C (4,221-4,442°F).
The density of Aluminium is 2.708 grams per cubic centimetre which is both malleable as well as ductile.
Uses Of Aluminium
Aluminium is utilized in a tremendous assortment of items including jars, foils, kitchen utensils, window outlines, lager barrels and plane parts. This is a result of its specific properties. It has a low thickness, is non-toxic, has high thermal conductivity, has incredible corrosion obstruction and can be easily cast, machined and shaped.
It is regularly utilized as alloy since Aluminium itself isn't stable. Compounds with copper, manganese, magnesium and silicon are lightweight however stable. They are significant in the development of planes and different types of transport.
The Biological Role Of Aluminium
Other than the three properties of Aluminium which are chemical properties of Aluminium as well as physical properties of Aluminium, no such biological role can be seen. +3 soluble in the plant makes it toxic. Acidic soils are due to the reaction of Aluminium with HCl found mostly on the Earth with AI3+ release from their minerals which the crops absorb.
Solved Example
1. What happens when there is a reaction of Aluminium with HCl?
The reaction of Aluminium with hydrochloric acid produces liquid aluminium chloride, AlCl3, as well as hydrogen gas, H2.
The chemical equation which is balanced explains this single replacement reaction that is
2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g)↑
Remember that this reaction of Aluminium with hydrochloric acid will not happen when we add the piece of Aluminium to the hydrochloric acid solution. This is because the piece of Aluminium is covered by a layer of aluminium oxide, Al2O3, which protects Aluminium reacting with the water. The hydrochloric acid will need some time to work through this layer, but once it happens, the reaction will proceed faster, i.e. bubbling can be seen in the hydrochloric acid.
Fun Fact
In more than 270 minerals, Aluminium mostly can be found.
It is one of the most abundant minerals on Earth after oxygen and also silicon.
Aluminium as a global scale is one of the most used metals which do not contain iron.
Aluminium reflects almost 98% of infrared rays and 92% visible light.
Currently, Australia can be said as the largest producer of Aluminium.
FAQs on Chemical Properties of Aluminium
1. What are the key chemical properties of Aluminium as per the CBSE syllabus?
Aluminium (Al) is a highly reactive metal with several important chemical properties. The main properties include:
- Reaction with Air: It reacts with oxygen to form a thin, tough, and protective layer of aluminium oxide (Al₂O₃) on its surface. This layer prevents further corrosion.
- Amphoteric Nature: It reacts with both acids and strong alkalis to produce salt and hydrogen gas.
- Reaction with Water: Aluminium does not react with cold or hot water, but it reacts with steam to form aluminium oxide and hydrogen.
- Reducing Agent: It acts as a powerful reducing agent, capable of extracting metals from their oxides, as seen in the thermite reaction.
2. Why does a shiny Aluminium utensil become dull after a few days?
A shiny Aluminium utensil becomes dull because Aluminium is a reactive metal that readily reacts with oxygen from the air. This reaction forms a thin, non-reactive, and protective layer of aluminium oxide (Al₂O₃) on its surface. While this layer prevents the metal from corroding further, it is not shiny, giving the utensil a dull appearance.
3. Why is Aluminium considered an amphoteric metal?
Aluminium is considered an amphoteric metal because it exhibits both acidic and basic properties. This means it reacts with both acids and strong bases. For example:
- With Acid (HCl): It forms aluminium chloride and hydrogen gas.
2Al(s) + 6HCl(aq) → 2AlCl₃(aq) + 3H₂(g) - With Base (NaOH): It reacts with a strong alkali like sodium hydroxide to form sodium aluminate and hydrogen gas.
2Al(s) + 2NaOH(aq) + 2H₂O(l) → 2NaAlO₂(aq) + 3H₂(g)
4. What is the difference between the physical and chemical properties of Aluminium?
The primary difference lies in what they describe. Physical properties can be observed without changing the chemical identity of the substance, while chemical properties describe how it reacts with other substances.
- Physical Properties of Aluminium: Include being silvery-white, lightweight, malleable, ductile, and an excellent conductor of heat and electricity.
- Chemical Properties of Aluminium: Include its reactivity with air, its amphoteric nature (reacting with both acids and bases), and its ability to act as a strong reducing agent.
5. How do the chemical properties of Aluminium make it useful in everyday life?
Aluminium's chemical properties directly contribute to its widespread use. The formation of a protective oxide layer makes it highly resistant to corrosion, which is why it's used for window frames, aircraft bodies, and kitchen foil. Its powerful role as a reducing agent is harnessed in the thermite process for welding railway tracks.
6. What is the thermite reaction and what is Aluminium's role in it?
The thermite reaction is a highly exothermic redox reaction where Aluminium powder is used as a reducing agent to reduce a metal oxide, most commonly iron(III) oxide. Aluminium's role is to pull oxygen away from the iron oxide, releasing a massive amount of heat that melts the iron. This molten iron is then used for welding, particularly for joining heavy iron parts like railway tracks.
7. Does Aluminium react with water? Explain why or why not.
Ordinarily, Aluminium does not appear to react with cold or hot water. This is not because it is unreactive, but because its surface is protected by a very thin but tough and impermeable layer of aluminium oxide (Al₂O₃). This layer forms instantly in air and prevents water from coming into contact with the pure metal underneath. However, if this oxide layer is removed, or if it reacts with steam at high temperatures, Aluminium will react to produce aluminium oxide and hydrogen gas.
