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 :

We are given two statements about corrosion and need to determine which are correct.

Analysis of Statement I:

Corrosion is an electrochemical process where a metal deteriorates due to reactions with its environment. According to the electrochemical theory of corrosion, a pure metal surface acts as the anode (where oxidation occurs), and impurities or other conducting surfaces act as the cathode (where reduction occurs). For example, in the rusting of iron, pure iron oxidizes at the anode: $$Fe -> Fe^{2+ + 2e^-}$$, while reduction occurs at the cathode on impurities. Thus, Statement I is true.

Analysis of Statement II:

The statement claims that corrosion is faster in an alkaline medium than in an acidic medium. However, corrosion rates are generally higher in acidic media because acids provide hydrogen ions ($$H+$$) that facilitate the cathodic reduction reaction. For instance, in acidic conditions, the cathode reaction is: $$2H+ + 2e^- -> H_{2}$$, which accelerates the overall corrosion process. In alkaline media, the low concentration of $$H+$$ ions slows down corrosion. Therefore, Statement II is false.

Conclusion: Statement I is true, but Statement II is false. The correct option is C.

Final Answer: C