Question detail

Chemical changes case 003 reactivity-evidence. A student uses the reactivity series to justify an observation. Which option is best? Focus on why less reactive metals may not react readily in Reactions of acids with metals, not on a neighbouring Unit 4.4 reaction idea.

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Reactions of acids

Question

A. Chemical changes case 003 reactivity-evidence: Uses the relative reactivity order to predict the change for why less reactive metals may not react readily
B. Chemical changes case 003 reactivity-evidence: Chooses the product by memorising a colour instead of the series (Reactions of acids with metals)
C. Chemical changes case 003 reactivity-evidence: Says any metal can displace any other metal ion (why less reactive metals may not react readily)
D. Chemical changes case 003 reactivity-evidence: Ignores whether the reacting substance is more or less reactive (Reactions of acids)

Answer

The correct option is Chemical changes case 003 reactivity-evidence: Uses the relative reactivity order to predict the change for why less reactive metals may not react readily.

Explanation

The correct option is Chemical changes case 003 reactivity-evidence: Uses the relative reactivity order to predict the change for why less reactive metals may not react readily. It is correct because it directly supports the approved learning objective to explain why less reactive metals may not react readily with dilute acids in Reactions of acids with metals. The other options are incorrect because they blur a Unit 4.4 concept boundary: acid versus alkali versus base, oxidation versus reduction, displacement versus reduction, electrolysis versus electroplating, anode versus cathode, positive versus negative ions, oxidation state versus ionic charge, or strong acid versus concentrated acid.

Common mistake

Misunderstanding reactivity series relevance

Students think all metals will react with dilute acids, ignoring the reactivity series and the fact that metals below hydrogen (e.g., zinc, iron) may not react readily with dilute acids.

Explain that only metals higher than hydrogen in the reactivity series (e.g., magnesium, zinc, iron) will displace hydrogen from dilute acids; metals below hydrogen (e.g., copper, silver) do not react with dilute acids because they are less reactive.

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For Reactions of acids with metals, which reaction focus answer best supports this Unit 4.4 objective: Explain why less reactive metals may not react readily with dilute acids?