Properties of Iron



1. Action of air:-

Dry air has no effect on iron but most air forms a brown layer of hydrated ferric oxide called Rust.

2Fe +  O2 + xH2O           →       Fe2O3.xH2O

Hydrated ferric oxide (Rust)

 

2. Action of Water:-

Cold water does not react with iron but when steam is passed over red hot iron,H2 gas is displaced.

Fe+H2O                 →                  Fe3O4 + H2

Red -hot steam                        Ferrosoferric oxide

 

3. Reaction with non-metals:-

Iron reacts directly with non-metals like halogens, sulphur carbon etc. to give respective compounds.

2Fe + 3Cl2           →                    2FeCl3

Ferric chloride

Fe + S                   →                   Fes

Ferous sulphide.

3Fe + C                    →               Fe3C

Iron carbidc or cementite.

 

4. Reaction with carbon monoxide:-

Iron reacts with CO at 1200C forming iron penta carbonys.

Fe + 5CO        120    →                Fe (CO)5

Iron pentacarbonyl

5. Reaction with acids:-

With dil. HCl and dil. H2SO4, iron gives ferrous salt along with H2 gas.

Fe + 2HCl               →                FeCl2 + H2

Dil.

Fe + H2SO4             →                FeSO4 + H2

Dil.

with hot and conc. H2SO4, iron gas a mixture of ferrous sulphate and ferric sulphate.

Fe + 2H2SO4               →           FeSO4 + SO2 + 2H2O

Conc.

2Fe + 2H2SO4               →          Fe2 (SO4)3 + SO2 + 2H2O

with dil HNO3, iron give nitrate and ammonium nitrate

4Fe + 10HNO3                      →              4Fe (NO3)2 + NH4NO3 + 3H2O

Dil

with mod conc. HNO3, iron gives Ferric nitrate and NO2 (Nitrogen dioxide).

Fe + 6HNO3                       →                 Fe (NO3)3 + 3NO2 + 3H2O.

with hot and conc. HNO3, Iron dose not react due to formation of an inert large of Fe3O4. This is called possivity of iron.