most of the metals acquires a dull surface when exposed to air name the chemical phenomenon responsible for this process state the condition under which the iron articles get rusted design in activity to investigate the conditions necessary for rusting .suggest any two methods to prevent rusting from iron
Answers
Answer:
While playing in your building compound, you might have come across an iron barbed wire which has turned red. You might have also seen some old metallic object at home. You would realise that these objects have turned reddish, unlike their original metallic colour. This is what we call rusting of iron.
Certain metallic objects develop changes on its surface. Being left stagnant for long or kept unused is the cause for this to happen. This is Corrosion. Corrosion consequently leads to gradual degradation of metals. Rusting is one of the ways of corrosion in metals. It happens to Iron and its Alloys. Iron objects consequently react with the Oxygen in the air and get rusted in a humid environment. Rust is Iron Oxide.
Methods used to prevent Rusting of Iron are as follows:
Alloying – Since Rusting of Iron is a chemical process that happens because the metal is attaining more stable chemical state, alloying (mixing) the iron with other stable metals or alloys can slow down the process of rusting.
Galvanizing – Galvanizing a metal object means to coat the surface of that object with a layer of metallic zinc. Also, it is an inexpensive procedure. In conclusion, it will provide it with protection against rusting.
Coating and Painting – Coating the surface of a metal object with a layer of either Paint or Varnish will break the contact between the surface and atmospheric oxygen making it consequently immune to rusting.
Humidity Control – Controlling the humidity of the environment is also a solution. Therefore, the chances of the metal object rusting will reduce.
Explanation:
The metals lose their shine or brighthness on keeping in air for a long time and acquire a dull apperance due to the formation of a thin layer of oxide, carbonate or sulphide on thier surface by the slow action of the various gases present in air
It is called corrosion