Acids, bases and salts

17 Which statement is correct? A Ethanoic acid is a weak acid because when it is added to excess alkali not all of the ethanoic acid reacts. B Ethanoic acid is a weaker acid than sulfuric acid because a smaller proportion of its molecules dissociate in aqueous solution. C Hydrochloric acid is a stronger acid than ethanoic acid because hydrochloric acid always has a higher pH than ethanoic acid. D Sulfuric acid is a strong acid because it produces two hydrogen ions for every molecule that dissociates.

© UCLES 2025 5070/11/O/N/25 18 Some properties of a solid oxide are listed. ● It reacts with dilute sulfuric acid giving a salt and water. ● It is insoluble in water. ● It reacts with aqueous sodium hydroxide. Which oxide is being described? A aluminium oxide B magnesium oxide C phosphorus( V ) oxide D sodium oxide 9

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39 Sulfur dioxide is a gas that is prepared by heating sodium sulfite with hydrochloric acid. It is an acidic gas. Sulfur dioxide is more dense than air. Which set of apparatus is suitable for preparing and collecting a dry sample of sulfur dioxide? A sodium sulfite + hydrochloric acid calcium oxide heat B C D sodium sulfite + hydrochloric acid concentrated sulfuric acid heat sodium sulfite + hydrochloric acid concentrated sulfuric acid heat sodium sulfite + hydrochloric acid concentrated sulfuric acid heat

5070/22/M/J/25 © UCLES 2025 1 Choose from the following salts to answer the questions. aluminium sulfate barium chloride copper( II ) nitrate copper( II ) sulfate magnesium chloride potassium iodide potassium manganate( VII ) silver chloride sodium bromide Each salt can be used once, more than once or not at all. State which salt: (a) is prepared using a precipitation reaction ............................................................................................................................................. [1] (b) gives a yellow flame test colour .....................................

5070/31/M/J/25 © UCLES 2025 1 Solid A is impure calcium carbonate. You are going to determine the number of moles of calcium carbonate in A by reacting it with excess 0.250 mol / dm 3 hydrochloric acid. The unreacted acid in this mixture is then titrated with 0.100 mol / dm 3 sodium hydroxide. You are provided with a sample of A. Read all the instructions carefully before starting the experiments. Instructions (a) Preparation of mixture B • Place the sample of A in a 250 cm 3 beaker. • Use a measuring cylinder to add 100 cm 3 of 0.250 mol / dm 3 hydrochloric acid, HCl, to the beaker. • Stir th

5070/31/M/J/25 © UCLES 2025 3 You are not expected to do any experimental work for this question. Q is a mixture of solid magnesium oxide and solid barium sulfate. Magnesium oxide is insoluble in water. It reacts with dilute hydrochloric acid to make a solution of magnesium chloride. Barium sulfate is insoluble in water and does not react with dilute hydrochloric acid. Plan an investigation to obtain pure magnesium chloride crystals and pure barium sulfate solid from Q. Your plan should describe the use of common laboratory apparatus, dilute hydrochloric acid and Q. No other chemicals should b