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CAIE A-Level Chemistry 7.2.7 Neutralisation Reactions

Practise recognising neutralisation and representing the essential reaction between aqueous hydrogen and hydroxide ions.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • write the net ionic equation H+(aq) + OH−(aq) → H2O(l) with states and balanced charge
  • remove spectator ions from a full acid–alkali equation to expose the neutralisation step
  • distinguish this equation from reactions where OH− deprotonates NH4+ to form NH3 and H2O

7.2.7—Neutralisation reactions occur when H +(aq) question 1

[Maximum number: 2]

A neutralisation reaction occurs when NaOH(aq) is added to H2SO4(aq)\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}). equation 1

2NaOH(aq)+H2SO4(aq)→Na2SO4(aq)+2H2O(I)2 \mathrm{NaOH}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \rightarrow \mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{I})

Question (a)

(a)

In an experiment, 50.0 cm350.0 \mathrm{~cm}^{3} of 2.00 moldm−3NaOH(aq)2.00 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{NaOH}(\mathrm{aq}) is added to 60.0 cm360.0 \mathrm{~cm}^{3} of 1.00moldm−3H2SO4(aq)1.00 \mathrm{moldm}^{-3} \mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) in a polystyrene cup and stirred. Both solutions have a temperature of 21.4∘C21.4^{\circ} \mathrm{C} before mixing. The maximum temperature of the mixture is measured.

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Question (i)

(i)

Use equation 1 to calculate the amount, in mol, of H2SO4(aq)\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) that is neutralised in the experiment.
amount of H2SO4\mathrm{H}_{2} \mathrm{SO}_{4} neutralised = .............................. mol

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Question (b)

(b)

The enthalpy change of neutralisation of CH3COOH(aq)\mathrm{CH}_{3} \mathrm{COOH}(\mathrm{aq}) and NaOH(aq) is −55.2 kJ mol−1-55.2 \mathrm{~kJ} \mathrm{~mol}^{-1}.

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Question (i)

(i)

Complete the equation for the reaction.

……….CH3COOH+……….NaOH→\ldots \ldots \ldots . \mathrm{CH}_{3} \mathrm{COOH}+\ldots \ldots \ldots . \mathrm{NaOH} \rightarrow
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