Question

1)State and explain in brief different methods to prevent rusting of iron

2)What is displacement reaction give an example

Answer 1

Rusting occurs when iron combines with the oxygen in the air causing it to corrode. Rust can affect iron and its alloys, including steel. Water is the main catalyst for the occurrence of rust. Salt water increases the speed of rusting.

Stainless steel and Weathering steel seem to be the most common type of way to prevent rust.

However there are other methods that are to be considered helpful in the prevention of rusting. Few are explained below:

1 ) Galvanization -
It involves coating surface of metal with an external layer of metallic zinc. Its possible through hot dip galvanizing or electroplating. The zinc layer prevents corrosive substances from penetrating further into the metal.

2) Coating -
Here the surfaces of iron/metal are coated with paint or grease.
Plating - Metals that can rust can be covered with less reactive metals or non reactive metals.

3) Alloying -
It is the mixture of two or more metals or non metals. Metals which cannot wear easily are melted into their molten form and are used to cover metals which rust easily. Thus stopping the iron or alloy from rusting.

4) Regular Maintenance
- It is important to have regular maintenance checks to make sure that corrosion isn’t occurring, in case if rust does begin appearing it is best to use a sharp thin blade to remove it. After that, using warm water and soap solution will clean the dirt which the rust has began creating. Finally, apply a coat of a rust resistance to the surface.


Answer 2 :

Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions.

Example : Reaction of iron nails with copper sulphate solution.