Question

In electrochemical corrosion, the metal undergoing corrosion:
A. acts as anode
B. acts as cathode
C. undergoes reduction
D. liquifies

Answer 1

Electrochemical corrosion generally happens when any two dissimilar materials that are having different electrode potentials are present in close contact with each other in the presence of a corrosive fluid.

Complete answer:
- If we see the electrochemical corrosion in case of metals, then it is seen that the pure metal acts as anode and impurity acts as cathode.
- It is also observed that in the anode region, the metal is oxidised to cation and in the cathode region, oxygen is reduced to water.
- Corrosion of iron that is also called rusting, is the most common example of electrochemical corrosion. This happens when iron comes in contact with air or with water.
-Corrosion can be prevented by various process like:
- Electroplating: In this process a metal is coated with a thin layer of other metal by using electrolysis.
- Galvanization: It is a process in which coating of iron is done with a thin layer of zinc. The zinc layer coating protects iron from corrosion on the inner side.
- Hence, we can say that the correct option is (A) that is in electrochemical corrosion, the metal undergoing corrosion acts as anode.

Note:
There are several factors that promote electrochemical corrosion are:
- Temperature- As temperature increases, corrosion also increases.
- Presence of impurities like salts, will also increase corrosion.