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Q66 (NDA-II/2017) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry Answer Verified

Zinc is used to protect iron from corrosion because zinc is

Result
Your answer: —  Â·  Correct: A
Explanation

Zinc is used to protect iron from corrosion through a process called galvanization [2]. This protection is effective because zinc is more electropositive (more reactive) than iron, meaning it has a higher tendency to ionize and lose electrons. In the electrochemical series, zinc is anodic to steel and iron [1]. Consequently, zinc acts as a sacrificial anode, preferentially corroding to protect the underlying metal even if the coating is scratched or broken [1]. While iron would normally oxidize to form rust, the presence of the more active zinc ensures that the zinc ions are formed instead, providing cathodic protection. Although zinc is a bluish-white metal and a good conductor, these physical properties are not the functional reason for its use in corrosion prevention; rather, its chemical reactivity and position in the galvanic series are the decisive factors.

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.5.1 Prevention of Corrosion > p. 54
  2. [2] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > Activity 4.5: Let us experiment > p. 50
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