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Give reason (a) Why does an alkaline medium inhibit the rusting of iron ? (b) Why does a dry cell become dead after a long time even if it has not been used ? (c) Why is zinc better than tin in protecting iron from corrosion ? |
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Answer» Solution :(a) Rusting of IRON takes place in the presence of `H^+`. Alkaline medium neutralises `H^+` ions and inhibits the process of rusting. (b) A dry cell becomes dead after a LONG time even if it has not been used. This is because acidic `NH^4Cl` which is a salt of weak base and STRONG acid, corrodes zinc container. (c) Zinc protects iron from corrosion because reduction potential of `Zn^(2+)` is lower than that of `Fe^(2+)`, but that of `SN^(2+)`is higher than that of `Fe^(2+)` . |
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