Preventing rusting by using sacrificial protection
2 marks · NormalState what is meant by a sacrificial anode, and name a metal commonly used as one to protect iron.
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A sacrificial anode is a more reactive metal attached to iron, which corrodes instead of the iron. Magnesium (or zinc) is commonly used.
Also accept: A metal attached to iron that corrodes in place of the iron; magnesium or zinc.
Common mistakes: Not stating that the metal must be more reactive.
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Marking points
B1 · 1 mark · Defines sacrificial anode as a more reactive metal or as a metal that corrodes instead of iron.
B2 · 1 mark · Names magnesium or zinc as the common example.
Worked solution
A sacrificial anode is a more reactive metal attached to iron, which corrodes in preference to the iron. Magnesium or zinc is commonly used as a sacrificial anode.