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Corrosion is a redox reaction that takes place in the presence of oxygen and water - NSC Physical Sciences - Question 8 - 2018 - Paper 2
Question 8
Corrosion is a redox reaction that takes place in the presence of oxygen and water. Rusting is the corrosion of iron leading to the formation of iron(III) ions. A c... show full transcript
Worked Solution & Example Answer:Corrosion is a redox reaction that takes place in the presence of oxygen and water - NSC Physical Sciences - Question 8 - 2018 - Paper 2
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8.1.4 Explain the above observation by referring to the Table of Standard Reduction Potentials.
Answer
The observation that the iron nail rusts while the copper rod does not can be explained by examining the Standard Reduction Potentials. Iron, with a lower reduction potential than copper, is more prone to oxidation. Therefore, it loses electrons more readily compared to copper, which is the more noble metal. Consequently, the iron nail oxidizes, forming rust (iron(III) ions), while the copper rod remains unchanged.
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8.1.5 You are given two metals, Zn and Cu, to use as metal Q. Which metal would more suitable? Give a reason.
Answer
The more suitable metal to use as metal Q would be zinc (Zn). Zinc has a lower standard reduction potential compared to iron, making it a better sacrificial anode. It will corrode preferentially over iron, thus preventing rusting of the iron pipe.