Practise 25 real questions on Nitrogen and sulfur from 2021 to 2026. See the answer and explanation as soon as you answer.
Nitrogen and sulfur is one of the 18 main topics in our A Level Chemistry (Cambridge (CAIE) 9701) question bank, and about 4% of its real questions come from it. Tayyari Karo has 25 real questions on this topic from 2021 to 2026, from Paper 1, Paper 2, Paper 4; 19 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 15 medium, 7 hard, 3 easy.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
Four reactions: 1 N2(g) reacts with O2(g); 2 NaOH(aq) reacts with NH4Cl(aq); 3 NH3(aq) reacts with HNO3(aq); 4 SO2(g) reacts with O2(g). Which reactions produce a basic soluble gas?
Answer: D. 2 only
Only reaction 2 releases NH3, a basic soluble gas.
Which statement is correct?
Answer: B. Aqueous ammonia contains both NH3(aq) and NH4⁺(aq). The NH4⁺(aq) ion is a Brønsted–Lowry acid.
NH4⁺ can donate a proton (NH4⁺ ⇌ NH3 + H⁺), so it is a Brønsted–Lowry acid; N2 is unreactive due to its strong triple bond (not lack of lone pairs, and not a double bond).
Three statements: 1) In aqueous solution, ammonia molecules form coordinate bonds with hydroxide ions. 2) Ammonium ions are Brønsted–Lowry acids. 3) The H–N–H bond angle is larger in the ammonium ion than in the ammonia molecule. Which statements are correct?
Answer: C. 2 and 3 only
Ammonia molecules do not form dative bonds with OH− (statement 1 is false — NH3 accepts H+ from water instead); NH4+ can donate a proton so it is a Brønsted–Lowry acid (statement 2 true); NH4+ is tetrahedral (109.5°) versus NH3's pyramidal 107° due to lone pair repulsion, so the bond angle is larger in NH4+ (statement 3 true).
A student reacts 1 mol of copper with concentrated nitric acid to produce 1 mol of copper(II) nitrate, 2 mol of water and substance X. No other product is formed. Substance X does not contain copper or hydrogen. What could be substance X?
Answer: D. NO2
Concentrated nitric acid reacting with copper is reduced to NO2: Cu + 4HNO3 → Cu(NO3)2 + 2H2O + 2NO2.
Carbon monoxide, CO, nitrogen dioxide, NO2, and sulfur dioxide, SO2, are all atmospheric pollutants. Which reaction occurs in the atmosphere? A CO is spontaneously oxidised to CO2. B NO2 is reduced to NO by SO2. C NO2 is reduced to NO by CO. D SO2 is oxidised to SO3 by CO2.
Answer: B. NO2 is reduced to NO by SO2.
In the atmosphere, SO2 reduces NO2 to NO while itself being oxidised to SO3 (which forms sulfuric acid); CO is not spontaneously oxidised without a catalyst, and CO2 cannot oxidise SO2.
Sulfur dioxide can be catalytically oxidised by an oxide of nitrogen in the atmosphere. Which reaction shows how the catalyst is reformed?
Answer: D. NO + ½O2 → NO2
NO acts catalytically: NO oxidises SO2 to SO3 while itself being reduced to... actually NO2 oxidises SO2 and is reformed by NO + ½O2 → NO2, regenerating the catalyst NO2.
| Session | Paper 1 | Paper 2 | Paper 4 |
|---|---|---|---|
| May/June 2026 | 1 | 1 | – |
| May/June 2025 | 2 | – | – |
| October/November 2025 | 2 | – | 1 |
| May/June 2024 | 1 | – | 1 |
| October/November 2024 | 1 | – | – |
| May/June 2023 | 1 | 1 | – |
| October/November 2023 | 1 | – | – |
| May/June 2022 | 4 | 1 | – |
| October/November 2022 | 3 | – | – |
| May/June 2021 | 2 | – | – |
| October/November 2021 | 1 | 1 | – |
25 real A Level Chemistry (9701) questions on Nitrogen and sulfur from 2021 to 2026, from Paper 1, Paper 2, Paper 4. Each one shows the year, session and paper it came from.
Yes. Every question shows the correct answer and a short explanation the moment you answer.
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