### Theory:

What is a chemical property?
A chemical property is a property of a substance that can be seen when it undergoes a chemical reaction.
Chemical Properties of Aluminium:

(a). Reaction with air:

Aluminium is not affected by dry air.
Aluminium burns brightly at $$800$$°C to form its oxide and nitride.

$$4Al$$ + $$3O_2$$ → $$2Al_2O_3$$ (Aluminium oxide).
$$2Al$$ + $$N_2$$ → $$2AlN$$ (Aluminium nitride).

(b). Reaction with water:

Water does not react with aluminium because of the oxide layer on it. When steam is passed over, the red hot aluminium produces hydrogen.

$$2Al$$ + $$3H_2O$$ → $$Al_2O_3$$ + $$3H_2$$↑
(Aluminium) + (Steam) → (Aluminium oxide) + (Hydrogen)

(c). Reaction with alkalis:

Aluminium reacts with caustic soda alkalis to form aluminates.

$$2Al$$ + $$2NaOH$$ + $$2H_2O$$ → $$2NaAlO_2$$ + $$3H_2$$↑
(Aluminium) + (Caustic soda) → (Sodium meta-aluminate)

(d). Reaction with acids:

Aluminium reacts with dilute or con. $$HCl$$ liberates $$H_2$$ gas.

$$2Al$$ + $$6HCl$$ → $$2AlCl_3$$ + $$3H_2$$↑
(Aluminium) + (Hydrogen chloride) → (Aluminium chloride) + (Hydrogen)

Aluminium reacts with dilute sulphuric acid releases hydrogen, similarly reacts with hot concentrated sulphuric acid releases sulphur dioxide.

$$2Al$$ + $$3H_2SO_4$$ → $$Al_2(SO_4)_3$$ + $$3H_2$$↑
(Dilute)
$$2Al$$ + $$6H_2SO_4$$ → $$Al_2(SO_4)_3$$ + $$6H_2O$$ + $$3SO_2$$↑
(Con.)
Important!
Dilute or concentrated nitric acid does not react with aluminium, but it does render it passive by forming an oxide film on its surface.
(e). Reducing agent:

Aluminium is a highly effective reducing agent.
When a mixture of aluminium powder and iron oxide is ignited, the latter is reduced to metal. This process is known as the aluminothermic process.
$$Fe_2O_3$$ + $$2Al$$ → $$2Fe$$ + $$Al_2O_3$$ + Heat.

Uses of Aluminium:

Aluminium is used in various applications.

(a). Household utensils.

Aluminium utensils

(b). Electrical cable industry.

Aluminium cables

(c). Manufacturing of aeroplanes and other industrial machinery parts.

Industrial usage of aluminium