Question

What would be the most durable metal plating on the iron to protect it against corrosion?
A) Nickel plating
B) Tin plating
C) Copper plating
D) Zinc plating

Answer 1

Hint:We know very well that according to electrochemical series a more reactive element placed at the top can easily displace a less reactive element placed at bottom from their salt solution and we also know the process of galvanisation where one metal is coated with other metal to prevent it from rusting.


Complete step by step solution:
As we know that according to electrochemical series a more reactive element placed at the top can easily displace a less reactive element placed at bottom from their salt solution. The electrochemical series follows the order:
\[Li > K > Ca > Na > Mg > Al > Mn > Zn > Cr > Fe > Co > Ni > Cu > I > Hg > Ag > Pt > Au > Br > Cl > F\] So, we can make out the fact that zinc is placed higher and iron is placed lower in the electrochemical series and thus iron is less reactive than zinc, so we can say that when zinc plating is added to the iron metal to protect it from corrosion.
This process is called galvanisation where protective covering of zinc is applied to iron or steel so as to prevent them from rusting or corrosion.
The other options are not correct because copper, nickel and tin all are present below iron and thus they are less reactive and iron can displace them easily.

Therefore, from the above explanation we can say that the correct answer is (D).


Note:Always remember that the zinc metal is widely used for covering or coating purposes of iron surfaces because even if any scratches or any damage takes place then also the iron will be safe from rusting as zinc undergoes oxidation because its reduction potential is lower than that of iron.

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