Which one of the following materials is most likely to be corroded? a. a wooden plank              b. a steel chair c. an exposed iron rod       d. an iron rod coated with oil.

48 Why does an aluminium vessel loose its shine so soon after use? 49 Silver does not combine easily with oxygen but silver jewellery tarnishes after sometime? Why? 51 What is corrosion? What are the ways to retard this process? 52 Compare the properties of metals and nonmetals with respect to malleability, ductility and conductivity