Question

Process of depositing a layer of zinc on iron objects is called as __
(A) Rusting
(B) Corrosion
(C) Sublimation
(D) Galvanisation

Answer 1

Hint: Galvanization is the technique of applying a thin zinc layer to metals such as iron or steel. The zinc coating assists to prevent corrosion of the metal. Galvanization can be accomplished using three main methods. Electrodeposition and electrochemical are two less frequent techniques, whereas hot dip galvanization is the most common. Immersing the metal in a zinc bath is the core concept underlying the hot dip technique.

Complete answer:
Galvanization is the process of coating steel or iron with a protective zinc coating to prevent corrosion. The most popular process is hot-dip galvanising, which involves immersing the components in molten zinc. The underlying iron or steel is protected in several ways by galvanising:
When the zinc coating is intact, it prevents corrosive chemicals from accessing the steel or iron beneath.
Additional electroplating, such as a chromate conversion coating, may be added to the substrate material to give additional surface passivation. The zinc functions as a sacrificial anode, sacrificing itself to preserve the underlying metal. Protection can be maintained even if the underlying metal is exposed as long as there is zinc close enough to be electrically linked. Localized corrosion of the base metal can occur after all of the zinc in the immediate region has been consumed.
Galvanizing will protect the underlying steel from attack, but rusting will occur after a few decades of contact to the elements, especially if exposed to acidic environments. Despite the protective function of the zinc coating, corrugated iron sheet roofing will begin to deteriorate after a few years. Galvanized iron's lifetime is further shortened in marine and salty settings because sea water's strong electrical conductivity accelerates corrosion, largely by turning solid zinc to soluble zinc chloride, which is easily washed away. Galvanized vehicle frames are a good example of this; they corrode considerably more quickly in cold areas owing to road salt, yet they survive longer than unprotected steel.
Hence option D is correct.

Note:
If further precautions, such as paint coatings and extra sacrificial anodes, are taken, galvanised steel can endure for decades. Sulfur dioxide levels in the air play a major role in the rate of corrosion in non-salty settings.