Question

Using the e values of a and b, predict which is better for coating the surface ofiron [e (fe2+ | fe) = 0.44 v] to prevent corrosion and why ?Given : e(a2+ | a) = 2.37 v : e(b2+| b) = 0.14 v

Answer 1

Answer: a is better  for coating the surface of iron.

Explanation:

Corrosion is the process of slow eating away of metal due to attack of atmospheric gases on the surface of metal resulting into formation of compounds such as oxides, sulfides , carbonates etc is called as corrosion.

Corrosion of iron is called as rusting.

Anode: $Fe\righatarrow Fe^{2+}+2e^-$

Cathode: $O_2+4H^++4e^-\rightarrow 2H_2O$

Thus to protect iron from corrosion it has to be coated with a metal which lose electrons on its behalf and has more negative reduction potential than iron.

Given:  $E^o_{Fe^{2+}/Fe}=-0.44V$

$E^o_{a^{2+}/a}=-2.37V$

$E^o_{b^{2+}/b}=-0.14V$

Thus a with more negative reduction potential will be used.