Reactions of Metals Exam Questions
Practice IGCSE Chemistry exam questions on reactions of metals. Covers reactions with water, dilute acids, and oxygen, writing equations, and predicting products from the reactivity series with mark schemes and examiner notes.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
These questions cover reactions of metals. Write full answers before checking.
Question 1 (4 marks, Core)
Describe the reactions of potassium, calcium, and copper with cold water. For each metal, state the products and the vigour of the reaction.
Mark scheme
- Potassium: very vigorous reaction, burns with a lilac flame, produces potassium hydroxide and hydrogen [1]
- Calcium: less vigorous, sinks then rises, steady effervescence, produces calcium hydroxide and hydrogen [1]
- Copper: no reaction with cold water [1]
- The pattern shows decreasing reactivity: K > Ca, and Cu is below hydrogen in the reactivity series so cannot displace it [1]
Examiner note: The general equation for Group 1/2 metals with water is: metal + water → metal hydroxide + hydrogen. The vigour decreases down the reactivity series. Metals below hydrogen (Cu, Ag, Au) do not react with water at all.
Question 2 (3 marks, Core)
Write balanced symbol equations for:
(a) Magnesium reacting with dilute sulfuric acid. (1)
(b) Iron reacting with steam. (1)
(c) Sodium reacting with water. (1)
Mark scheme
(a) Mg + H2SO4 → MgSO4 + H2 [1]
(b) 3Fe + 4H2O → Fe3O4 + 4H2 [1]
(c) 2Na + 2H2O → 2NaOH + H2 [1]
Examiner note: Note the difference: metals that react with cold water form hydroxides; metals that react only with steam form oxides. Iron does not react with cold water but reacts with steam. Magnesium reacts very slowly with cold water but vigorously with steam and with dilute acid.
Question 3 (3 marks, Core)
When magnesium ribbon is burned in air, it burns with a bright white flame and produces a white powder.
(a) Name the white powder. (1)
(b) Write the balanced equation. (1)
(c) State the type of reaction. (1)
Mark scheme
(a) Magnesium oxide [1]
(b) 2Mg + O2 → 2MgO [1]
(c) Oxidation / combustion [1]
Examiner note: Most metals react with oxygen to form metal oxides. The vigour of the reaction depends on the metal’s position in the reactivity series. Magnesium burns very brightly; iron requires strong heating and only forms an oxide coating.
Question 4 (4 marks, Core)
Complete the table to show what happens when each metal is added to dilute hydrochloric acid.
| Metal | Observation | Products | Equation |
|---|---|---|---|
| Magnesium | ? | ? | ? |
| Zinc | ? | ? | ? |
Mark scheme
| Metal | Observation | Products | Equation |
|---|---|---|---|
| Magnesium | Vigorous fizzing / effervescence, metal dissolves [1] | Magnesium chloride + hydrogen | Mg + 2HCl → MgCl2 + H2 [1] |
| Zinc | Steady fizzing, metal dissolves slowly [1] | Zinc chloride + hydrogen | Zn + 2HCl → ZnCl2 + H2 [1] |
Examiner note: The general equation is: metal + acid → salt + hydrogen. Mg reacts more vigorously than Zn because Mg is higher in the reactivity series. The salt name depends on the acid used (HCl → chloride, H2SO4 → sulfate).
Question 5 (3 marks, Supplement)
Explain why aluminium does not appear to react with dilute hydrochloric acid initially, even though it is higher than zinc in the reactivity series.
Mark scheme
- Aluminium has a thin, tough layer of aluminium oxide (Al2O3) on its surface [1]
- This oxide layer is unreactive and prevents the acid from reaching the aluminium metal underneath [1]
- Once the oxide layer is dissolved or removed, aluminium reacts vigorously with the acid [1]
Examiner note: The aluminium oxide layer forms instantly when aluminium is exposed to air. It is very thin but very protective. This is why aluminium appears less reactive than expected — it is protected by its oxide coating. In reality, aluminium is very reactive.
Question 6 (3 marks, Core)
A student heats iron filings in a stream of steam. A black solid forms and a gas is given off.
(a) Name the black solid. (1)
(b) Name the gas and state the test for it. (1)
(c) Write the balanced equation. (1)
Mark scheme
(a) Iron(II,III) oxide / tri-iron tetraoxide (Fe3O4) [1]
(b) Hydrogen gas; test with a burning splint — squeaky pop [1]
(c) 3Fe + 4H2O → Fe3O4 + 4H2 [1]
Examiner note: Iron reacts with steam but not cold water. The product Fe3O4 is a mixed oxide containing both Fe2+ and Fe3+ ions. The reaction is reversible at high temperatures.
Question 7 (3 marks, Supplement)
Predict and explain what happens when:
(a) Gold is placed in dilute hydrochloric acid. (1)
(b) Zinc is heated in steam. (2)
Mark scheme
(a) No reaction — gold is below hydrogen in the reactivity series and is too unreactive to displace hydrogen from acid [1]
(b) Zinc reacts with steam to form zinc oxide (ZnO) and hydrogen gas [1] Zn + H2O → ZnO + H2 [1]
Examiner note: Use the reactivity series to make predictions. Metals above hydrogen react with acids and/or water/steam. Metals below hydrogen do not. The more reactive the metal, the more vigorous the reaction.
What to revise if you scored below 5
If you struggled to write equations, learn the three patterns: metal + acid → salt + H2; reactive metal + water → hydroxide + H2; less reactive metal + steam → oxide + H2. Revisit the reactions of metals notes.
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