Question

The process of zinc plating on iron sheet is known_ _ _ _ _
(A) Annealing
(B) Roasting
(C) Galvanization
(D) Smelting

Answer 1

The process of coating a thin layer of metal on a solid substrate is called plating. When this process is carried out using electricity, then it is called electroplating. The current is provided by an external power supply.

Complete step by step answer:
(A) Annealing is a heat treatment process which alters the microstructure of a material to change its mechanical or electrical properties. The chemical properties of a material also get changed so as to improve the work above abilities or properties of the material.
However the process of plating does not involve any change in the properties of the substrate. Thus this option cannot be correct.
(B) The process of roasting involves the heating of an ore for its processing lower than its melting point in the presence of air or oxygen.
On the other hand, the process of plating cannot be done using ore. It do requires the manufactured from of one i.e. metal
(C) Galvanisation is the process of applying a protective layer of zinc coating on steel or iron.
(D) Smelting is a form of extractive metallurgy which helps to produce metal from its ore by applying heat and using a chemical reducing agent to decompose the ore. The other elements like gasses or slag are derived off from the ore, to leave behind the pure metal.
Now the process of applying zinc coating on iron does not involve the ore.

Hence the answer is option (C).

Additional Information:
The zinc protects iron by corroding first. For better results. Application of chromates over zinc is also seen as an industrial trend.
The zinc coating, when intact, prevents the corrosive substance from reaching the underlying steel or irons.

Note:
In the event of corrosion, the underlying metal becomes exposed, protection can continue as long as there is zinc in the immediate area is consumed, localized corrosion of the base metal can occur.