Consider the following metals: Ag, Au, Mg, Ni, and Zn. Which of these metals could be used as a sacrificial anode in the cathodic protection of an underground steel storage tank? Steel is an alloy composed mostly of iron, so use −0.447 V as the standard reduction potential for steel.
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Chemistry 2e · 17.6 Corrosion
Corrosion: practice problems
3 problems from the book, with its answers. Check your working, or have any of them explained to you on the whiteboard.
Exercises 40
If a sample of iron and a sample of zinc come into contact, the zinc corrodes but the iron does not. If a sample of iron comes into contact with a sample of copper, the iron corrodes but the copper does not. Explain this phenomenon.
Exercises 42
Why would a sacrificial anode made of lithium metal be a bad choice
Key terms · 5
- cathodic protection
- approach to preventing corrosion of a metal object by connecting it to a sacrificial anode composed of a more readily oxidized metal
- corrosion
- degradation of metal via a natural electrochemical process
- galvanization
- method of protecting iron or similar metals from corrosion by coating with a thin layer of more easily oxidized zinc.
- sacrificial anode
- electrode constructed from an easily oxidized metal, often magnesium or zinc, used to prevent corrosion of metal objects via cathodic protection
- salt bridge
- tube filled with inert electrolyte solution
Learn 17.6 on the whiteboard
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