The following factors play vital role in corrosion process: A.Temperature B.Pressure C.Both A and B D.None of the above
Hint: We can define corrosion as the process through which metals reach their more stable state. In this stable state the metals form the metal’s oxides, sulphides or metal hydroxides. Corrosion of iron is called rusting and iron forms its oxides and the colour also changes.
Complete answer: Corrosion is defined as the process of the formation of a more stable state of the metal where the metal forms metal oxides, metal sulphides and metal hydroxides. What happens is that these metals when left in the open contact with air and moisture gets to the environment so as to form the corroded state of the metal. The process of corrosion is an undesirable process because what happens is that it negatively affects the physical properties of the metals. For example, what happens with iron is the iron reacts with the air and moisture present in its surrounding and gets corroded and forms ferrous oxide. Now this corroded state of the iron makes it lose its high tensile strength. The process of conversion of metals into their corroded form is an irreversible reaction as they form their stable oxides. Factors affecting or playing a vital role in the corrosion process are: Exposure of the metals to air Presence of impurities, this makes the process go faster and easier Exposure to moisture Temperature – an increase in the temperature increases the amount and rate of corrosion Nature of the first layer of oxide because what happens is that if the first layer is unreactive it shields the rest of the metal from corrosion Presence of acids in the atmosphere: acids have the capability to accelerate the process of corrosion Therefore, temperature plays a vital role in corrosion.
Note: Sometimes few metals like iron which have a high tensile strength and takes a lot of money to make a layer of another material of cheap price which itself forms its corroded form of oxide and shield the rest of the iron from getting in contact with air and moisture. Aluminium is sometimes used for this process. This process is called shielding.