When iron undergoes corrosion,it .........

Given below are two statements:
Statement $I$: Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode.
Statement $II$: The rate of corrosion is more in alkaline medium than in acidic medium.
In the light of the above statements,choose the correct answer from the options given below:

To protect iron against corrosion,the most durable metal plating on it is:

The chemical formula of rust is:

Which of the following metals corrodes readily in moist air?

Which of the following statements regarding the rusting of iron is incorrect?