Tag: changes around us

Rusting of iron is corrosion of iron. Rusting of iron takes place when iron corrodes in the presence of water and oxygen. It is a redox reaction whereby oxygen acts as an oxidising agent while iron acts as a reducing agent. When iron is contact with water, a simple chemical cell is formed.

• One of the properties of iron is that it reacts with oxygen in the presence of moisture and gets corroded by forming rust.
• Air contains oxygen and moisture. Hence, iron readily rust when exposed to air.
• Steel (stainless steel, not mild steel) is an alloy of iron having the property to resist corrosion including rusting. Hence, stainless steel, though it contains iron, does not undergo corrosion. 

In the activity series, metals are on the top of the series react and corrode easily as these metals are highly reactive like iron corrodes easily in the presence of water and air forming its oxide layer while metals present at the bottom are least reactive and do not corrode easily like gold, silver and platinum are some of them.

If edible oil is allowed to stand for a long time in an iron or tin container the fatty acids in the oil react with rust flakes or powder to form salts. These salts contaminate the oil and hence the oil becomes rancid. Thus the above statement is true.

'X' is copper (Cu) and the black-coloured compound formed is copper oxide(CuO). The equation of the reaction involved on heating copper is given below:

The $Na^{\oplus}$ and $Cl^{\ominus}$ present in saline water increase the conductance of the solution in contact with the metal surface. This accelerates the formation of $Fe^{2+}$ ions and hence that of rust, $Fe _2O _3 \cdot xH _2O$

Rust is an iron oxide, usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Given sufficient time, oxygen and water, any iron mass will eventually convert entirely to rust and disintegrate. No rusting takes place in absence of moisture. 

Oxide of iron is rust. Iron in presence of oxygen forms iron oxide. The chemical name of rust is ferrous oxide. It further oxidises to ferric oxide.

Corrosion resistance of aluminium is due to formation of thin layer of aluminium oxide that forms when metal is exposed to air and prevents further oxidation. It is called as protective passivation.

Corrosion is basically oxidation of metal in presence of oxygen. So it can be prevented by cutting off ${ O } _{ 2 }$