Reactions of metals with dilute acids

2 marks · Normal

Describe two observations you could make when magnesium is added to dilute hydrochloric acid that show it is more reactive than iron.

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Also accept: Magnesium reacts more vigorously (faster fizzing/bubbling) and causes a greater temperature rise than iron.; More fizzing and a hotter test tube for magnesium compared to iron.

Common mistakes: Only comparing colours or using incorrect metals.

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Marking points

B1 · 1 mark · States that magnesium reacts more vigorously/produces more fizzing than iron.

B2 · 1 mark · States that the temperature rise (or heating) is greater for magnesium than for iron (or mentions test tube gets hotter).

Worked solution

Magnesium produces much more vigorous fizzing than iron, showing more rapid production of gas.

The test tube with magnesium gets much hotter than the one with iron, indicating a greater temperature change.