Question

Write in brief about corrosion?

Answer 1

$\huge \text{CORROSION:}$

• Surface of many metals is easily attacked when exposed to air.

• They react with air or water or pollutants present in the atmosphere and form undesirable compounds on their surfaces.

• Thus corrosion is a process of eating away of the metal surface as a result of air ,water or pollutants present in the environment.

Corrosion of iron:

• Iron when exposed to moisture and air gets covered by a brown coloured flaky substance called rust. Chemically rust is hydrated iron oxide. Rusting is an oxidation process.

Corrosion of Copper:

• When a copper object is exposed to moist air for sometime, then copper slowly reacts with carbon dioxide, moisture and air to form a green coating of basic copper carbonate on the surface.

• Since copper is unreactive metal, corrosion of copper is very slow.

Corrosion of silver:

• Silver is an unreactive metal ,so it does not react with air or water.

• But it slowly reacts with air pollutant like hydrogen sulphide to form a black layer of silver sulphide.

Corrosion of aluminium:

• Due to the formation of dull layer of aluminium oxide when exposed to moist air, the aluminium metal looses its shine very soon.

• This layer is very tough and prevents aluminium metal underneath from further corrosion.Here corrosion is useful .

Answer 2

Corrosion:

The rust of iron ( iron oxide ), tarnishing of silver ( silver sulphide) ,development of green coating on copper ( copper carbonate) and bronze are some of the examples of corrosion ☠︎☠︎