" 18.Why do we apply paint on iron articles? "

Why do we apply paint of iron articles ?

Metals get attacked by substances around it such as moisture, acids, etc. Metal is said to 'corrode' due to this attack and the process is called corrosion. Many metals like iron, copper, silver, etc. get corroded. When iron is exposed to moist air, it undergoes corrosion and a reddish brown coloured solid layer is formed on its surface. Corrosion of iron, which is known as rusting, is a serious problem as enormous amount of money is spent every year to replace damaged iron. Similarly, copper reacts with moisture and. CO_(2) in air to form a green coloured coating of basic copper carbonate on its surface. Silver acquires a black colour when exposed to air containing H_(2)S due to the formation of silver sulphide on its surface. Based on the above paragraph, answer the following question. Why do we apply paint on iron articles?

(i) Solid calcium oxide was taken in a container and water was added slowly to it : (a) Write the observation . (b) Write the chemical formula of the product formed (ii) What happens when carbon dioxide gas is bubbled through lime water : (a) In small amount , (b) In excess? (iii) Why do you apply paint on iron articles ?

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