Reactions of metals with dilute acids
2 marks · HardA student places strips of magnesium and iron into separate test tubes containing excess dilute hydrochloric acid at room temperature. Only one test tube becomes noticeably warm and gives off gas rapidly.
State which metal is more reactive and explain your reasoning using the observations.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Magnesium is more reactive because it reacts rapidly and gives off heat and gas quickly; this is shown by the test tube becoming noticeably warm and producing gas rapidly compared to iron.
Also accept: Magnesium is more reactive as shown by faster gas production and larger temperature rise.
Common mistakes: Reversing the order: saying iron is more reactive based on the data.; Not mentioning both gas and temperature observations.
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Identifies magnesium as the more reactive metal based on results.
A1 · 1 mark · Justifies answer using correct experimental observations (e.g. faster gas production, greater temperature rise, more heat out).
Worked solution
Magnesium is more reactive than iron because the test tube with magnesium gets noticeably warm and produces gas rapidly, showing a faster and more vigorous reaction.