Question

Galvanized iron sheets are coated with:
(A) Copper
(B) Nickel
(C) Zinc
(D) Carbon

Answer 1

Hint: The process of applying a protective coating of metal to steel or iron to prevent it from rusting is known as Galvanization or Galvanizing.

Complete step by step solution:
-In the process of Galvanization, the coating of zinc is done on any other metal surface which is less reactive than zinc to protect it from corrosion.
-Zinc reacts with the weather at a very slow rate, so the coating of zinc protects the inner metal from reaction with the weather and provides it with a very long life.
-Galvanization, when done on steel, increases the strength of steel and provides a more delightful appearance.
-Since, zinc has a greater electronegativity than iron, hence it provides specific protection to the steel from the outer environment.
-The most common method for galvanization is hot-dip galvanizing, in which parts are submerged in a bath of molten zinc.
-The process of galvanization protects the underlying iron or steel metal in the following main ways-
(i) Zinc coating when intact, prevents the contact of air and moisture with ion or copper, hence preventing rusting.
(ii) Zinc protects iron or silver by providing an extra layer of it and corroding it first. An application of chromates over zinc is also seen as an industrial trend.
(iii) In the event of galvanization, the protection is continued as long as there is zinc enough to be electrically coupled. When the layer of galvanizing is removed, the metal area becomes exposed hence corrosion occurs.

So, the correct answer is option (C).

Note: When iron and oxygen react in the presence of water or air moisture, a reddish-brown oxide is formed in this deposit over the metal surface and is known as Rust. Rust reaction is a redox reaction. Rust contains hydrated ion oxides and iron (III) oxide-hydroxide. Oxygen is a very good oxidizing agent while the iron is a very good reducing agent, therefore the iron atoms readily give up the electrons when exposed to oxygen.