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.
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.
Wrought iron (iron-containing < \(0.25\)% of carbon):
(c). Wrought iron is used to make springs, anchors, and electromagnets.
Wrought iron usages