Question

Zinc can be coated on iron to produce galvanized iron but reverse is not possible. It is because:
A. zinc has lower negative electrode potential than iron
B. zinc has higher negative electrode potential than iron
C. zinc is lighter than iron
D. zinc has lower melting point than iron

Answer 1

Hint: The reduction potential of an element tells the ease of reduction of an element. When two elements are compared, the elements having low negative reduction potential will get reduced and the elements having high negative reduction potential will get oxidized.

Complete step by step solution:
The electrochemical series is a series of elements, in which elements are arranged according to their reduction potential.
The reduction potential of zinc is $ - 0\,.76{\text{v}}$ and the reduction potential of iron is $ - 0.44\,{\text{v}}$. So, the iron has low negative reduction potential and zinc has high negative reduction potential. So, iron will reduce and zinc will oxidize.
Iron gets oxidized in presence of moisture which is known as rusting. To protect the iron, it is coated with zinc because zinc has a higher negative reduction potential than iron, so zinc gets oxidized before iron, so it protects the iron from getting oxidized.
The reverse is not possible because even if the zinc is coated with iron means iron will be in contact with moisture, zinc will get oxidized first due to high negative reduction potential.

Therefore option (B) zinc has higher negative electrode potential than iron, is correct.

Note: The species which accept electrons is known as reduced and the process is known as reduction. The opposite process in which the species release electrons is known as oxidation. In an electrochemical series in which the elements are arranged with high reduction potential on top to low reduction potential on the bottom, the species present above will get reduced. The species present below will get oxidized.