Chapter 5 Practice Paper: Acids and Bases — question paper

Section A: Multiple-choice questions[10 marks]

Choose the one correct answer for each question.

1. 1

   Aqueous ammonia is classified as an alkali because, in water, it

   1. Acontains ammonium metal ions
   2. Bproduces hydroxide ions
   3. Cturns Universal Indicator red
   4. Dis a soluble salt
   ( )
2. 2

   Universal Indicator is dipped into a solution of pH 10. The colour seen is

   1. Ared
   2. Byellow
   3. Cindigo
   4. Dgreen
   ( )
3. 3

   Dilute hydrochloric acid is added to iron filings. The gas evolved

   1. Aburns with a squeaky pop
   2. Bturns limewater milky
   3. Cturns damp red litmus blue
   4. Dbleaches damp litmus white
   ( )
4. 4

   An oxide is added to dilute hydrochloric acid and it dissolves; another sample dissolves in aqueous sodium hydroxide too. Which oxide shows this behaviour?

   1. AMgO
   2. BCO₂
   3. CAl₂O₃
   4. DCO
   ( )
5. 5

   Which equation represents neutralisation?

   1. AH⁺(aq) + OH⁻(aq) → H₂O(l)
   2. BH⁺(aq) + O²⁻(aq) → H₂O(l)
   3. CNa⁺(aq) + Cl⁻(aq) → NaCl(aq)
   4. DCaCO₃(s) → CaO(s) + CO₂(g)
   ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Show all necessary working. Give numerical answers to 3 significant figures where appropriate, with units.

1. 1

   Solutions of three household substances are tested with Universal Indicator.

   Indicator test results

   Substance	Indicator colour	pH
   lemon juice	red	2
   bicarbonate of soda solution		9
   distilled water

   1. (a)

      Complete the indicator colour and pH for the bicarbonate of soda solution.

      [2]
   2. (b)

      Complete the indicator colour and pH for distilled water.

      [2]
   3. (c)

      Explain, in terms of ions, why the lemon juice solution has the lowest pH of the three.

      [2]
2. 2

   Zinc granules are added to dilute sulfuric acid and the gas collected and tested.

   1. (a)

      Write the balanced equation, with state symbols, for the reaction.

      [3]
   2. (b)

      Name the salt formed.

      [1]
   3. (c)

      State the test and the positive result for the gas evolved.

      [1]
3. 3

   A community garden has soil with a pH of 4.0, and the vegetables grow poorly.

   1. (a)

      Name the chemical the gardeners should spread on the soil.

      [1]
   2. (b)

      Explain, in terms of ions, how the treatment raises the soil pH.

      [2]
   3. (c)

      State one risk of spreading too much of the chemical.

      [1]
   4. (d)

      The gardeners also store an ammonium fertiliser next to bags of lime. Explain why the bags should be kept apart.

      [1]
4. 4

   Four oxides are studied: sodium oxide (Na₂O), sulfur dioxide (SO₂), zinc oxide (ZnO) and carbon monoxide (CO).

   1. (a)

      For each oxide, state whether it is acidic, basic, amphoteric or neutral: Na₂O, SO₂, ZnO, CO.

      [2]
   2. (b)

      Rainwater containing dissolved sulfur dioxide damages limestone statues. Explain why, naming the compound class responsible.

      [2]