Question

Assertion :The rusting on the surface of iron involves following reaction :
a. $Fe\left(s\right)\to F{e}^{2+}\left(aq\right)+2e^{-}$ (at anodic site)
b. $O_2\left(g\right)+4H^{\oplus }\left(aq\right)+4e^{-}\to 2H_{2}O\left(l\right)$ (at cathodic site)
c. $4F{e}^{2+}\left(aq\right)+O_2\left(g\right)+4H_{2}O\left(l\right)\to 2F{e}_2{O}_3\left(s\right)+8H^{\oplus }$
d. $F{e}_2{O}_3\left(aq\right)+x{H}_{2}O\left(l\right)\to F{e}_2{O}_3.x{H}_{2}O$ Reason: Rusting is accelerated in the presence of $NaCl$ and $C{O}_2$

Read the above assertion and reason and choose the correct option regarding it.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Corrosion is basically an electrochemical phenomenon. The rusting of iron, the tarnishing of silver, development of a green coating on copper and bronze are some of the examples of corrosion. Corrosion causes enormous damage to building, bridges, ships and to many other articles made of iron. We spend crores of rupees every year on this account. In corrosion, a metal is oxidised by loss of electrons to oxygen and forms metal oxide. Corrosion of iron(which is commonly known as rusting) occurs in presence of water and oxygen (air).