Nitrogen and sulfur — AS & A Level Chemistry (9701) questions by topic
Qualitative analysis and acid-base reasoning combine in this topic: deciding which procedure for burning sulfur and adding NO or NO2 is correct, identifying compound L from its empirical formula and conductivity, and evaluating statements about ammonia and ammonium-ion bonding.
Identify, deduce, describe, state and express are the top command words across 31 questions from 2023 to 2025 papers, worth 1 to 19 marks, where thorough observation notes matter as much as the chemistry itself. Practising qualitative-test descriptions with instant marking flags an incomplete colour-change observation or a missing starting colour before the same gap in test-writing recurs in the next ion-identification question.
What examiners look for
- A recurring criticism is giving an incomplete observation when more than one reagent or condition was required.
- Examiners note candidates should record the starting colour for observations involving a colour change, and be thorough noting every observation for unfamiliar tests or gases.
- A common misconception described a weak acid as one that 'did not completely dissolve' rather than one that partially dissociates.
- Strong scripts appreciated they were distinguishing nitrate, nitrite and ammonium ions and provided a suitable table, scoring well when selecting the correct reagent for each ion.
- Candidates who described a weak Bronsted-Lowry acid accurately as a proton donor that only partially dissociates in solution were rewarded.
May–June 2025, Paper 11
Which reduction process occurs on the surface of a catalytic converter? A reduction of carbon dioxide and nitrogen oxides B reduction of carbon dioxide only C reduction of…
Answer this question and get it marked →May–June 2025, Paper 12
In the Haber process, the reaction between the two gaseous reactants requires the use of a catalyst that contains a transition element. What is the metal and in which mole ratio…
Answer this question and get it marked →Sulfur dioxide in the atmosphere can form acid rain. This occurs in two steps: 1 oxidation of SO2 to SO3 2 formation of dilute H2SO4 Which row identifies the atmospheric catalyst…
Answer this question and get it marked →May–June 2025, Paper 13
The flow chart shows some reactions of nitrogen compounds. gas 1 →(acid)→ salt 1 →(alkali)→ salt 2 + other products Which row identifies gas 1 and salt 2? A gas 1 = ammonia, salt…
Answer this question and get it marked →Which dot-and-cross diagrams represent molecules that can react with unburned hydrocarbons to form peroxyacetyl nitrate, PAN, a component of photochemical smog? (Diagrams 1–4…
Answer this question and get it marked →May–June 2025, Paper 14
Compound L has empirical formula NH. It decomposes on gentle heating to produce ammonia and compound M only. An aqueous solution of compound L is a good conductor of electricity.…
Answer this question and get it marked →May–June 2024, Paper 11
Nitrogen dioxide is a gas that contributes to air pollution. It is produced in internal combustion engines. Which statement is correct? A Nitrogen dioxide acts as a catalyst in…
Answer this question and get it marked →May–June 2024, Paper 12
Which statement describes a property of an ammonium ion? A An aqueous ammonium ion is a weak Bronsted-Lowry base. B Aqueous ammonium sulfate reacts with dilute hydrochloric acid…
Answer this question and get it marked →Catalytic converters are fitted in the exhaust systems of many cars. Gas X: - causes acid rain if it is released into the air - is removed from car exhaust fumes by a catalytic…
Answer this question and get it marked →May–June 2024, Paper 13
NH4Cl reacts with NaOH in an aqueous solution. Which statement is correct? A The reaction gives rise to two different polar product molecules. B The bond angle in the…
Answer this question and get it marked →What is produced when 60 g of nitrogen monoxide reacts with an excess of carbon monoxide in a catalytic converter? A 12 g of carbon and 92 g of nitrogen dioxide B 24 g of carbon…
Answer this question and get it marked →May–June 2024, Paper 23
Explain the lack of reactivity of nitrogen gas, N2(g).
Answer this question and get it marked →October–November 2024, Paper 11
Three statements about ammonia molecules and ammonium ions are given. 1 In aqueous solution, ammonia molecules form coordinate bonds with hydroxide ions. 2 Ammonium ions are…
Answer this question and get it marked →October–November 2024, Paper 12
A reaction between two gases takes place on the surface of the catalytic converter of a petrol-engined car. In this reaction, four reactant molecules produce three product…
Answer this question and get it marked →Which statement is correct? A An ammonium ion is basic due to a lone pair of electrons on the nitrogen atom. B Nitrogen monoxide, NO, reacts with peroxyacetyl nitrate to produce a…
Answer this question and get it marked →October–November 2024, Paper 13
Three statements about ammonia molecules and ammonium ions are given. 1 In aqueous solution, ammonia molecules form coordinate bonds with hydroxide ions. 2 Ammonium ions are…
Answer this question and get it marked →October–November 2024, Paper 22
Nitrogen and phosphorus are elements in Group 15 of the Periodic Table. Nitrogen is found in inorganic compounds such as nitrogen oxides (NOx), nitrates and nitric acid. Identify…
Answer this question and get it marked →February–March 2023, Paper 12
Two procedures are described. 1 Sulfur is burned in an excess of oxygen and then NO is added to the product mixture. 2 Sulfur is burned in an excess of oxygen and then NO2 is…
Answer this question and get it marked →May–June 2023, Paper 11
The Contact process takes place at a pressure between 100 000 Pa and 200 000 Pa. A catalyst is used. Which statement is correct? A A V2O5 catalyst is added to increase the…
Answer this question and get it marked →The solids sodium chloride and sodium iodide both react with concentrated sulfuric acid at room temperature. With NaCl, the products are NaHSO4 and HCl. With NaI, the products are…
Answer this question and get it marked →Which emission from an internal combustion engine contributes to the erosion of marble statues? A carbon monoxide B nitrogen C nitrogen dioxide D unburnt hydrocarbons
Answer this question and get it marked →May–June 2023, Paper 12
J dissolves in water to give an aqueous solution K. K gives a dense white precipitate when aqueous silver nitrate is added. When heated with aqueous potassium hydroxide, K gives…
Answer this question and get it marked →Ammonium sulfate, (NH4)2SO4, and ammonium nitrate, NH4NO3, are used as fertilisers. These salts have different percentages by mass of nitrogen. They have the same effect as each…
Answer this question and get it marked →The equation shows a reaction that occurs between carbon monoxide and nitrogen monoxide in a catalytic converter. 2CO(g) + 2NO(g) - 2CO2(g) + N2(g) Which statement is correct? A…
Answer this question and get it marked →May–June 2023, Paper 13
Which particle contains nitrogen in the same oxidation state as in the ion N2O5^2-? A NH2F B N2O4 C NO3- D HNF2
Answer this question and get it marked →Which statement about the oxides of nitrogen is correct? A During lightning storms, atmospheric oxygen and nitrogen combine to form oxides of nitrogen. B In a catalytic converter,…
Answer this question and get it marked →October–November 2023, Paper 12
When concentrated sulfuric acid is added to solid sodium chloride, HCl is formed but not Cl2. When concentrated sulfuric acid is added to solid sodium iodide, I2 is formed. Which…
Answer this question and get it marked →NaOH(aq) is added to NH4Cl(aq) and the mixture is warmed. The gas that is produced turns damp red litmus paper blue. Which row is correct for the behaviour of the ammonium ion in…
Answer this question and get it marked →October–November 2023, Paper 13
If ammonium cyanate is heated in the absence of air, the only product of the reaction is urea, CO(NH2)2. No other products are formed in the reaction. What is the formula of the…
Answer this question and get it marked →October–November 2023, Paper 22
Phosphoric(V) acid, H3PO4, is used in both inorganic and organic reactions. H3PO4 is made in a two-step process from phosphorus. Step 1: Phosphorus reacts with an excess of oxygen…
Answer this question and get it marked →October–November 2023, Paper 35
FA 6, FA 7 and FA 8 are salts, each of which contains nitrogen. Each of the nitrogen-containing ions is different and all are shown in the Qualitative analysis notes. List the…
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