Galvanization is applying a coating of:

We start by recalling what the process called “galvanization” actually means in metallurgy and corrosion science. Galvanization is a protective technique in which a base metal, most commonly iron or steel, is covered with a thin, adherent layer of a second metal that is more reactive toward oxidation, so that it preferentially corrodes and thereby shields the underlying iron or steel from rusting.

To understand why a particular metal is chosen, we remember the basic principle of sacrificial protection. A metal that is more easily oxidized, i.e., that lies above iron in the electrochemical series, will oxidize first. Its oxide layer or the metal itself forms a barrier, and any corrosive environment attacks this sacrificial layer rather than the base metal.

Among the given options, let us examine each metal in turn:

Option A gives copper, written chemically as $$Cu$$. Copper stands below iron in the electrochemical (activity) series, meaning it is less reactive than iron. If copper were coated on iron, the iron would actually corrode faster at any pinholes or scratches, because copper would act as a cathodic region. So copper is not used for galvanization.

Option C supplies lead, $$Pb$$. Lead is again less reactive than iron and is soft and toxic; though lead coatings are sometimes used for acid-resistant purposes, the word “galvanization” does not refer to applying lead.

Option D lists chromium, $$Cr$$. Chromium is indeed used for “chromium plating,” also called “chrome plating,” which gives shiny, corrosion-resistant finishes. However that is a different process, commonly referred to as electroplating or hard chrome, not galvanization in the traditional sense.

Option B presents zinc, $$Zn$$. Zinc lies above iron in the electrochemical series, meaning it is more easily oxidized. When a coating of zinc covers iron or steel, the following advantages arise:

1. The zinc layer forms a physical barrier that keeps oxygen and moisture away from the iron surface.
2. Even if the coating is scratched, zinc continues to corrode preferentially, offering sacrificial, cathodic protection to the exposed iron.

Because of these dual benefits, the industrial term “galvanization” specifically signifies applying a coating of zinc to iron or steel articles, often by hot-dip methods or electro-galvanizing.

After analyzing all the choices, only zinc satisfies the exact definition and practical usage of galvanization.

Hence, the correct answer is Option B.