CBSE Class 12 · 2000 · All India Compartment · Redox Reactions and ElectrochemistryVery Short Answer

Why does an alkaline medium inhibit the rusting of iron?

Solution

The electrochemical rusting of iron requires H

^{+}

ions — the cathodic reaction is O

_{2}

+ 4H

^{+}

+ 4e

^{-} \to

_{2}

O.
An alkaline medium removes (neutralises) the H

^{+}

ions, so this reaction, and hence rusting, is inhibited.

CBSE Class 12 Board · 2000 · All India Compartment · Subjective