Which of the following phenomenon we can observe in part A of the figure given below.
Corrosion
Corrosion is defined as the slow and steady destruction of a metal by the environment. It results in the deterioration of the metal to form metal compounds by means of chemical reactions with the environment.
Rusting of iron requires air and water. Iron articles are shiny when new, but get coated with a reddish brown powder called rust (Fe2O3.nH2O), when left for some time. This process is commonly known as rusting of iron.