What are the conditions necessary for the chemical change in iron?

Answer 1

Iron is an active metal that has a fairly strong tendency to lose electrons. This is called oxidation whereas gaining electrons is called reduction.

Fe(s) --> Fe2+ + 2e-

Iron most commonly loses electrons to oxygen to form iron oxide, rust, Fe2O3 but will lose electrons to other small non metal electronegative atoms as well.

Fe + O2 --> Fe2O3

Fe + Cl2 --> FeCl2

To protect the iron we can coat it or put it near zinc which has a stronger tendency to lose electrons than iron so sacrifices itself rather than the iron. This is called "sacrificial anodic protection". Iron can be coated with a non permeable barrier to keep it away from oxygen eg paint, plastic, grease or oil, or even a non corroding metal like chrome.

Answer 2

if you leave a piece of iron outside in moist air a reddish coating called rust forms on its surface.rust crumbles easily and sometimes falls off the iron ,leaving the surface of the iron pitted.

Answer 3

For the chemical change in iron to occur, three conditions are necessary: presence of oxygen (oxidizing agent), presence of water (electrolyte), and the iron surface needs to be exposed to these elements for the reaction to take place. This process is known as iron oxidation, leading to the formation of iron oxide (rust).