JEE Main 2016 · 10 Apr · Shift 1 · Chemistry Q47

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ChemistrySingle correct+4 / -1Question 47 of 90

Identify the correct statement :

Iron corrodes in oxygen-free water.

Iron corrodes more rapidly in salt water because its electrochemical potential is higher.

Corrosion of iron can be minimized by forming a contact with another metal with a higher reduction potential.

Corrosion of iron can be minimized by forming an impermeable barrier at its surface.

Answer and worked solution

Official answer: D

A protective barrier (paint, oil, a tin or zinc coat) keeps out water and oxygen and so limits corrosion. Iron needs oxygen to rust; salt water speeds rusting by conducting, not by changing iron's potential; and contact with a metal of higher reduction potential makes iron the anode and speeds corrosion.

Topics:Galvanic cells and EMF

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JEE Main 2016 · 10 Apr · Shift 1, Chemistry question 47