### Theory:

What is physical property?
A physical property is a property of matter that can be observed and measured without changing the sample's chemical identity.
Physical Properties of Iron:

(a). Iron is a lustrous (shiny and bright appearance) metal with greyish white colour. (You can see building construction)

Shiny greyish white iron

(b). Iron has a high tensile strength (of iron is $$60,000$$ psi), malleability and ductility.
Tensile strength is described as the ability of a material to resist a force that tends to pull it apart.
Malleable is drawn into a thin wire. Ductility is capable of being shaped.
Hard iron wires and sheets, etc.,

(c). Iron can be magnetized.
Magnetization is the process of developing the properties of a magnet in a magnetic object. A magnetic object such as a piece of iron can be magnetized by contact with electricity or a magnet.
Magnetized iron

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 Iron:

(i). Reaction with air or oxygen:

Iron forms magnetic oxide only when heated in the air.

$$3Fe$$ + $$2O_2$$ → $$Fe_3O_4$$ (black)

(ii). Reaction with moist air or Rusting:

Rust formation on an iron bolt
When iron is exposed to moist air, it forms a brown hydrated ferric oxide layer on its surface. This compound is known as rust, and the phenomenon of the formation of rust is known as rusting.
$$4Fe$$ + $$3O_2$$ + $$xH_2O$$ → $$2Fe_2O_3$$.$$xH_2O$$ (rust)

(iii). Reaction with steam:

When steam is passed over a red hot iron, the magnetic oxide is formed.

$$3Fe$$ + $$4H_2O$$ (steam) → $$Fe_3O_4$$ + $$4H_2$$↑

(iv). Reaction with chlorine:

Iron reacts with chlorine to form ferric chloride.

$$2Fe$$ + $$3Cl_2$$ → $$2FeCl_3$$ (ferric chloride)

(v). Reaction with acids:

Iron liberates $$H_2$$ gas with dilute $$HCl$$ and $$H_2SO_4$$.

$$Fe$$ + $$2HCl$$ → $$FeCl_2$$ + $$H_2$$↑
$$Fe$$ + $$H_2SO_4$$ → $$FeSO_4$$ + $$H_2$$↑

In cold conditions, dilute $$HNO_3$$ produces ferrous nitrate and ammonium nitrate.

$$4Fe$$ + $$10HNO_3$$ → $$4Fe(NO_3)_2$$ + $$NH_4NO_3$$ + $$3H_2O$$

With concentrated sulfuric acid, iron forms ferric sulfate and liberates $$SO_2$$.

$$2Fe$$ + $$6H_2SO_4$$ → $$Fe_2(SO_4)_3$$ + $$3SO_2$$ + $$6H_2O$$

When iron is dipped in concentrated nitric acid, it becomes chemically passive or inert due to forming a layer of iron oxide ($$Fe_3O_4$$) on its surface.

Types and Uses of Iron:

Pig iron (iron-containing $$2.0$$% - $$4.5$$% of carbon):

(a). Pig iron is used to make pipes, stoves, radiators, railings, utility covers, and drain pipes.

Pig ion usages

Steel (iron-containing $$0.25$$% - $$2.0$$% of carbon):

(b). Steel is used to construct buildings, machinery, transmission cables, television towers, and the manufacture of alloys.

Steel usages

Wrought iron (iron-containing < $$0.25$$% of carbon):

(c). Wrought iron is used to make springs, anchors, and electromagnets.

Wrought iron usages