why does a coating of tin on iron not give a chemical protection against the rusting of iron?

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why does a coating of tin on iron not give a chemical protection against the rusting of iron?

2007-03-12 09:26:16 · 2 answers · asked by sikhism4life88 1 in Science & Mathematics ➔ Chemistry

2 answers

To be an effective sacrificial protection (like zinc) the coating must be of a metal higher than iron in the reactivity series. Tin, however, is below iron, so is not an effective (chemical) sacrificial protection layer, only a physical one.

2007-03-12 09:40:55 · answer #1 · answered by Gervald F 7 · 0⤊ 0⤋

It does give protection. However when it is scratched so that the iron is exposed to moist air the exposed part can rust.

2007-03-12 16:29:42 · answer #2 · answered by Rich Z 7 · 0⤊ 0⤋