Reactions of metals with dilute acids
2 marks · EasyExplain, with reasons, why copper does not react when added to dilute hydrochloric acid, but magnesium reacts vigorously.
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Copper is below hydrogen in the reactivity series and does not displace hydrogen from acids. Magnesium is above hydrogen and can displace hydrogen, so it reacts vigorously.
Must show: Copper below hydrogen (no displacement), Magnesium above hydrogen (displaces hydrogen)
Common mistakes: Copper is less reactive, but not explaining with the reactivity series
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Marking points
B1 · 1 mark · Explains that copper is below hydrogen in the reactivity series and cannot displace hydrogen.
B2 · 1 mark · States that magnesium is above hydrogen and does displace hydrogen, so reacts vigorously.
Worked solution
Copper does not react with dilute hydrochloric acid because it is below hydrogen in the reactivity series, so it cannot displace hydrogen from the acid.
Magnesium is above hydrogen in the series and can displace hydrogen, causing a vigorous reaction.