Acid–base titrations

Which piece of apparatus is used to measure varying volumes of liquid during a titration?

Feb/March 2016

Which piece of apparatus is used to measure changing amounts of liquid in a titration?

Feb/March 2016

Barium hydroxide is an alkali that reacts with hydrochloric acid. What happens to the pH of the hydrochloric acid as excess aqueous barium hydroxide is added?

Feb/March 2019

In which salt preparation are a burette and a pipette used?

May/June 2017

Which method for preparing a salt makes use of a burette and a pipette?

May/June 2017

Which method of salt preparation involves the use of a burette and a pipette?

May/June 2017

A student needs to obtain an accurate volume of $25.00\,\text{cm}^3$ of dilute hydrochloric acid. Which apparatus is most suitable?

May/June 2019

$25.0\,\text{cm}^3$ of $0.100\,\text{mol dm}^{-3}$ aqueous sodium hydroxide is fully neutralised by $24.6\,\text{cm}^3$ of dilute sulfuric acid. Determine the concentration of the dilute sulfuric acid.

May/June 2019

What apparatus is used to measure out exactly $25.00\,\text{cm}^3$ of hydrochloric acid?

May/June 2021

The concentration of acids and alkalis may be found by titration. What apparatus is required to carry out a titration?

May/June 2023

A conical flask containing sodium hydroxide solution and a few drops of methyl orange indicator is titrated with dilute hydrochloric acid. Which apparatus is used to deliver the hydrochloric acid?

May/June 2023

The concentration of acids and alkalis may be determined using titration. Which pieces of apparatus are required to carry out a titration?

May/June 2023

A titration is used to determine the concentration of a dilute aqueous sodium hydroxide sample. The apparatus is shown. Which information is required to work out the concentration of the dilute aqueous sodium hydroxide in $\text{mol dm}^{-3}$?

May/June 2023

A conical flask containing sodium hydroxide solution and a few drops of methyl orange indicator is titrated with dilute hydrochloric acid. Which piece of apparatus is used to introduce the hydrochloric acid?

May/June 2023

What is used to determine the end-point of an acid-base titration?

May/June 2024

A student needs to measure out $25.00\ \text{cm}^3$ of dilute hydrochloric acid accurately. Which piece of apparatus is most appropriate?

May/June 2025

Which piece of apparatus would be used to measure $25.0\,\text{cm}^3$ of aqueous sodium hydroxide?

May/June 2025

Aqueous barium hydroxide, $\text{Ba(OH)}_2$, is allowed to react with dilute nitric acid, $\text{HNO}_3$. This produces aqueous barium nitrate, $\text{Ba(NO}_3)_2$, together with water. During a titration, $15.2\,\text{cm}^3$ of $0.75\,\text{mol dm}^{-3}$ aqueous barium hydroxide is needed to neutralise $20.0\,\text{cm}^3$ of dilute nitric acid. Calculate the concentration of the nitric acid.

May/June 2025

Jelly is a blend of water and protein chains. The diagram shows protein chains enclosed by water.

Oct/Nov 2016

What feature in the structure of fumaric acid shows that it is unsaturated?

Oct/Nov 2018

Determine the concentration of the dilute sulfuric acid by finding: the moles of aqueous potassium hydroxide used; the moles of dilute sulfuric acid needed to neutralise the aqueous potassium hydroxide; the concentration of the dilute sulfuric acid.

Oct/Nov 2018

Hydrochloric acid, HCl(aq), when dilute, reacts with aqueous sodium carbonate, Na_2CO_3(aq). The reaction is represented by the equation below. 2HCl + Na_2CO_3 → 2NaCl + CO_2 + H_2O

Oct/Nov 2019

Which diagram depicts a burette?

Oct/Nov 2020

Suggest why universal indicator is not appropriate for this titration.

Oct/Nov 2021

Which apparatus is used to measure out exactly $25.0\,\text{cm}^3$ of hydrochloric acid?

Oct/Nov 2022

Which burette has a reading of $12.1\,\text{cm}^3$?

Oct/Nov 2022

An acid-base titration is outlined. • $25.0\text{ cm}^3$ of dilute aqueous alkali is placed in a conical flask. • Indicator is then added to the flask. • Dilute acid is added to the aqueous alkali until the indicator changes colour. • The volume of acid used is then measured. Which piece of apparatus is used correctly?

Oct/Nov 2023

A description of an acid-base titration is given. • $25.0\,\text{cm}^3$ of dilute aqueous alkali is placed in a conical flask. • An indicator is then added to the flask. • Dilute acid is added to the aqueous alkali until a colour change occurs in the indicator. • The volume of acid used is then measured and recorded. Which way of using apparatus is correct?

Oct/Nov 2023

What apparatus would be used to measure out exactly $21.50\,\text{cm}^3$ of dilute sulfuric acid?

Oct/Nov 2024

Which row presents one advantage and one disadvantage of the apparatus named for use in a titration?

Oct/Nov 2024

A scientist carries out a titration to determine the concentration of acid in a lemon juice sample. First, a known volume of aqueous lemon juice and a few drops of indicator are placed in a flask. The aqueous lemon juice is then titrated with $0.1\,\text{mol dm}^{-3}$ aqueous sodium hydroxide. Which piece of apparatus is used to deliver the aqueous sodium hydroxide into the flask?

Oct/Nov 2024

An aqueous sodium hydroxide solution of known volume and concentration is titrated with dilute hydrochloric acid. The volume of dilute hydrochloric acid needed to bring about complete neutralisation of the sodium hydroxide is measured. Five calculation stages are listed below. 1 Calculate the moles of hydrochloric acid present. 2 Calculate the relative formula mass for hydrochloric acid. 3 Calculate the hydrochloric acid concentration in $\text{g dm}^{-3}$. 4 Calculate the moles of sodium hydroxide. 5 Calculate the hydrochloric acid concentration in $\text{mol dm}^{-3}$. What is the correct order of these steps to work out the hydrochloric acid concentration in $\text{g dm}^{-3}$?

Oct/Nov 2024

The reaction equation for dilute ethanoic acid with aqueous lithium hydroxide is given here: $\text{CH}_3\text{COOH} + \text{LiOH} \rightarrow \text{CH}_3\text{COOLi} + \text{H}_2\text{O}$. During an experiment, $20.0\,\text{cm}^3$ of $0.050\,\text{mol dm}^{-3}$ aqueous lithium hydroxide is completely neutralised by $12.5\,\text{cm}^3$ of dilute ethanoic acid. Which statement is correct?

Oct/Nov 2025

A student prepares crystals of the salt sodium sulfate, $\mathrm{Na_2SO_4}$. The student reacts 0.200 mol/dm$^3$ dilute sulfuric acid, $\mathrm{H_2SO_4(aq)}$, with aqueous sodium hydroxide, $\mathrm{NaOH(aq)}$. The student follows these steps. step 1 The student puts 40.0 cm$^3$ of $\mathrm{NaOH(aq)}$ into a conical flask. This volume contains 0.0100 moles of NaOH. step 2 The student adds a few drops of methyl orange indicator to the $\mathrm{NaOH(aq)}$ in the conical flask. step 3 The student adds 0.200 mol/dm$^3$ $\mathrm{H_2SO_4(aq)}$ to the flask until the end-point is reached. step 4 The student pours the mixture from the conical flask into an evaporating basin and gets dry crystals.

Oct/Nov 2025

A student carries out an investigation into the reaction between dilute hydrochloric acid and aqueous sodium hydroxide. The student carries out five experiments. Experiment 1 • Put aqueous sodium hydroxide into a burette. • Let some aqueous sodium hydroxide flow out of the burette until its level is on the burette scale. • Note the starting burette reading. • Use a volumetric pipette to place 25.0 cm$^3$ of dilute hydrochloric acid into a conical flask. • Place the conical flask on a white tile. • Add five drops of thymolphthalein indicator to the conical flask. • Gently add aqueous sodium hydroxide from the burette to the conical flask while swirling the flask, until the solution only just changes colour. This is the end-point. • Note the finishing burette reading. Experiment 2 • Discard the contents of the conical flask and wash it with distilled water. • Refill the burette with aqueous sodium hydroxide. • Let some aqueous sodium hydroxide flow out of the burette until its level is on the burette scale. • Note the starting burette reading. • Use the volumetric pipette to place 25.0 cm$^3$ of dilute hydrochloric acid into the conical flask. • Add 0.25 g of sodium hydrogencarbonate to the conical flask and swirl the flask. • Place the conical flask on the white tile. • Add five drops of thymolphthalein indicator to the conical flask. • Gently add aqueous sodium hydroxide from the burette to the conical flask while swirling the flask, until the solution only just changes colour. This is the end-point. • Note the finishing burette reading. Experiment 3 • Carry out Experiment 2 again, but use 0.50 g of sodium hydrogencarbonate instead of 0.25 g. Experiment 4 • Carry out Experiment 2 again, but use 1.00 g of sodium hydrogencarbonate instead of 0.25 g. Experiment 5 • Carry out Experiment 2 again, but use 1.50 g of sodium hydrogencarbonate instead of 0.25 g.

Oct/Nov 2025

A student studies how acidic solution B reacts with two different aqueous sodium hydroxide solutions, solution C and solution D, by using two indicators. The student carries out two experiments. Experiment 1 • Rinse a burette first with distilled water and then with solution C. • Fill the burette with solution C. Let some of solution C run out so that the liquid level is on the burette scale. • Note the initial burette reading. • Use a measuring cylinder to pour 25 cm$^3$ of solution B into a conical flask. • Add five drops of methyl orange indicator and five drops of thymolphthalein indicator to the conical flask. • Put the conical flask on a white tile. • Slowly add solution C from the burette to the conical flask, swirling the flask, until the solution changes colour from red to orange. This is the first end-point. • Note the burette reading at the first end-point. • Keep adding solution C from the burette to the conical flask while swirling the flask. The solution changes colour from orange to yellow. • Continue adding solution C, while swirling the flask, until the solution changes colour from yellow to green. This is the second end-point. • Note the burette reading at the second end-point. Experiment 2 • Empty the conical flask and rinse it with distilled water. • Repeat Experiment 1 with solution D instead of solution C.

Oct/Nov 2025