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Acids Bases and Salts — Free MYP5 Chemistry Practice Questions
1QuestionFiltering Crystallizing and Drying a SaltConcept Practice
2 marks~3 minCriterion A
During the preparation of copper sulfate crystals, a student sets up a filtration apparatus to remove excess copper oxide from sulfuric acid.
a
Identify the piece of equipment that holds the filter paper and directs the filtrate into the collection vessel below. [1]
b
Explain why filtration alone is insufficient to obtain pure, dry copper sulfate crystals from the filtrate. [1]
Solutions
2QuestionAcids in Industry Cleaning Fertilizers Battery AcidConcept Practice
2 marks~3 minCriterion A
A car battery contains six cells, each holding lead dioxide plates, lead plates, and a liquid electrolyte.
(a) Identify the acid used as the electrolyte in a car battery, giving its chemical formula. [2]
(a) Identify the acid used as the electrolyte in a car battery, giving its chemical formula. [2]
Solutions
3QuestionPhysical and Chemical Properties of BasesConcept Practice
2 marks~3 minCriterion A
The diagram below shows three substances: sodium hydroxide pellets () in a beaker, aqueous ammonia () in a bottle, and a strip of magnesium ribbon.
a
Identify one substance from the diagram that is classified as a base. [1]
b
Describe one observable physical property of the base you identified, as shown in the diagram. [1]
Solutions
4QuestionMeasuring pH Using Electronic and Paper MetersConcept Practice
2 marks~3 minCriterion A
A water quality technician tests a river sample using two instruments:
Instrument A — an electronic pH meter with a probe and digital display
Instrument B — a strip of pH paper compared against a colour chart
Instrument A — an electronic pH meter with a probe and digital display
Instrument B — a strip of pH paper compared against a colour chart
a
State which instrument provides a numerical pH reading and which provides a colour-based reading. [1]
b
The technician records pH 4.2 using Instrument A and observes an orange colour using Instrument B. Explain one advantage of using Instrument A over Instrument B when precise pH data must be reported. [1]
Solutions
5QuestionDefinition and Real-Life Examples of NeutralizationConcept Practice
3 marks~5 minCriterion A
When a patient takes an antacid tablet containing magnesium hydroxide, it reacts with excess hydrochloric acid in the stomach. The reaction reduces stomach acidity and relieves discomfort.
a
Construct the word equation for the neutralization reaction between magnesium hydroxide and hydrochloric acid. [1]
b
Explain why this reaction is classified as a neutralization, referring to the nature of the reactants and the products formed. [2]
Solutions
6QuestionPreparing Soluble Salts Using Different MethodsAssessment Practice
6 marks~9 minCriterion B
A student prepares copper(II) sulfate crystals by reacting copper(II) oxide with excess sulfuric acid. The table below shows results from five trials.
| Mass of CuO (g) | 2 | 4 | 6 | 8 | 10 |
|---|---|---|---|---|---|
| Mass of CuSO crystals (g) | 4.8 | 9.6 | 14.4 | 14.4 | 14.4 |
a
Interpret the pattern shown in the data. [2]
b
Deduce the mass of CuSO crystals produced when 5 g of CuO is used, and justify your reasoning using the data. [2]
c
Analyse why the mass of crystals does not increase beyond 6 g of CuO, identifying which reagent limits the reaction and explaining the chemical reason for this behaviour. [2]
Solutions
7QuestionPreparing Soluble Salts Using Different MethodsAssessment Practice
6 marks~9 minCriterion C
A student adds 0.5 M sodium hydroxide (NaOH) solution in 2 mL increments to 25 mL of 0.5 M hydrochloric acid (HCl), stirring continuously. The pH is recorded after each addition. The resulting titration curve is shown below.
[See graph: pH vs. Volume of NaOH added (mL)]
The curve starts at , rises gradually to approximately at 24 mL, then rises sharply to between 24 mL and 26 mL, before levelling off near .
[See graph: pH vs. Volume of NaOH added (mL)]
The curve starts at , rises gradually to approximately at 24 mL, then rises sharply to between 24 mL and 26 mL, before levelling off near .
a
Construct a calculation to determine the volume of NaOH solution required to completely neutralize the HCl. [2]
b
The student repeats the experiment using 0.5 M potassium hydroxide (KOH) instead of NaOH. Justify whether the volume of KOH required to reach the equivalence point would differ from your answer in part (a). [2]
c
The student claims that adding 30 mL of NaOH instead of 25 mL produces a stronger salt solution. Evaluate this claim, using the pH data and your knowledge of the products formed. [2]
Solutions
8QuestionTesting Salts for Solubility and IdentityAssessment Practice
8 marks~12 minCriterion D
A coastal chemical plant generates 5000 tonnes of salt waste annually — primarily and — dissolved in seawater and discharged as brine into the ocean, causing a 30% decline in local seagrass biodiversity. The company proposes instead evaporating the brine in land-based ponds to produce solid salt for sale as road de-icer. These ponds would be constructed above a freshwater aquifer.
a
Using solubility rules, deduce whether and will precipitate during evaporation in the ponds. [2]
b
Identify one environmental factor not described above that could affect the pond system, and explain how it would alter the risk to the aquifer. [2]
c
Evaluate the trade-offs between ocean discharge and the evaporation pond system, considering environmental, economic, and societal factors. In your answer, discuss why solubility data alone is insufficient to inform this decision. [4]
Solutions
9QuestionpH Control in Agriculture and Swimming PoolsAssessment Practice
2 marks~3 minCriterion B
A farmer tests the effect of adding lime (calcium oxide) to three soil types. The pH of each soil is measured after adding 0 g, 5 g, and 10 g of lime.
Peat soil has a natural pH of 4.5 with 0 g of lime added.
| Lime added (g): 0 | 5 | 10 |
|---|---|---|
| Sandy soil pH: 5.0 | 6.0 | 7.0 |
| Clay soil pH: 5.5 | 6.5 | 7.5 |
| Loamy soil pH: 6.0 | 7.0 | 8.0 |
Peat soil has a natural pH of 4.5 with 0 g of lime added.
a
Deduce the relationship between the mass of lime added and the pH change observed across all three soil types. [1]
b
A farmer needs peat soil to reach a pH of at least 6.5 for optimal crop growth. Evaluate whether adding 10 g of lime is sufficient, and justify your answer using the pattern from the data. [1]
Solutions
10QuestionBases in Everyday Products Soap Toothpaste Drain CleanersAssessment Practice
3 marks~5 minCriterion C
The bar chart below shows the time taken for drain cleaner (, a strong base) and soap (a mild base) to dissolve a fixed mass of grease. The saponification reaction is:
Drain cleaner dissolves the grease in 20 seconds; soap takes 100 seconds.
Drain cleaner dissolves the grease in 20 seconds; soap takes 100 seconds.
a
Describe the trend shown in the bar chart. [1]
b
Explain, using the concept of dissociation, why drain cleaner dissolves grease faster than soap. [1]
c
A student claims that doubling the concentration of the soap solution would make it dissolve grease at the same rate as drain cleaner. Evaluate this claim. [1]
Solutions
11QuestionRole of Acids and Bases in Environmental ChemistryAssessment Practice
5 marks~8 minCriterion D
A student investigates whether limestone () can neutralize sulfuric acid in a lake affected by acid rain. Two beakers each contain 500 mL of water at pH 4.0, adjusted with . Beaker A contains 10 g of limestone chips; Beaker B contains no limestone. pH is recorded every 2 hours for 24 hours. The graph below shows the results.
a
Write the balanced chemical equation for the reaction between limestone and sulfuric acid. [1]
b
Explain how this reaction accounts for the pH trend observed in Beaker A. [2]
c
Evaluate the hypothesis that limestone effectively neutralizes sulfuric acid in aquatic ecosystems, using both the experimental evidence and at least two limitations of the experimental design. [2]
Solutions
12QuestionCommon Examples and Uses of Acids and BasesAssessment Practice
2 marks~3 minCriterion B
A student tests four household substances with red cabbage indicator and records the following results.
| Substance | lemon juice | vinegar | baking soda solution | soap solution |
|---|---|---|---|---|
| pH | 2 | 3 | 9 | 10 |
| Indicator colour | red | red | blue | blue |
a
Identify the pattern relating pH to the colour of red cabbage indicator. [1]
b
A scientist tests milk (pH 6) and tomato juice (pH 4) with red cabbage indicator. Both solutions appear the same colour. Deduce whether this result supports or contradicts the pattern you identified in (a), and justify your reasoning. [1]
Solutions
13QuestionCommon Examples and Uses of Acids and BasesAssessment Practice
3 marks~5 minCriterion C
When hydrochloric acid reacts with marble chips (calcium carbonate), carbon dioxide gas is produced. A student measures the volume of produced per minute at three acid concentrations, keeping temperature, mass of marble chips, and surface area constant.
Results:
Results:
| Concentration (mol dm): 0.1 | 0.5 | 1.0 |
|---|---|---|
| Rate of produced (cm min): 2 | 10 | 20 |
a
Describe the trend shown in the data. [1]
b
Explain, using collision theory, why increasing the concentration of hydrochloric acid increases the rate of reaction. [1]
c
A student claims that doubling the concentration always doubles the rate of reaction. Evaluate this claim using the data provided. [1]
Solutions
14QuestionConductivity of Acidic and Basic SolutionsAssessment Practice
5 marks~8 minCriterion D
A student collects rainwater from three locations and records the following data:
| Location A (near an industrial city) | pH = 4.2 | conductivity = 850 µS/cm |
|---|---|---|
| Location B (in a forest) | pH = 5.6 | conductivity = 45 µS/cm |
| Location C (coastal area) | pH = 5.9 | conductivity = 120 µS/cm |
a
Explain why the conductivity of the rainwater at Location A is significantly higher than at Location B. [2]
b
Location C has a higher conductivity than Location B despite having a less acidic pH. Explain what this suggests about the relationship between conductivity and acid pollution. [1]
c
Discuss the limitations of using conductivity as the sole indicator of water pollution or ecological harm, using data from all three locations to support your answer. [2]
Solutions
15QuestionEveryday Substances and Their pH ValuesAssessment Practice
3 marks~5 minCriterion B
The pH values of six household substances are listed below.
| Substance | pH value |
|---|---|
| Lemon juice | 2.5 |
| Vinegar | 3.0 |
| Milk | 6.5 |
| Pure water | 7.0 |
| Baking soda solution | 8.5 |
| Soap solution | 10.0 |
a
Identify the neutral substance from the list. [1]
b
Classify each remaining substance as acidic or basic, using its pH value as evidence. [1]
c
Analyse how the data shows a trend in acidity and alkalinity across the six substances, and explain what this trend reveals about the relationship between pH and the strength of acidity or alkalinity. [1]
Solutions
16QuestionStrong vs Weak Acids and Bases ConceptualAssessment Practice
2 marks~3 minCriterion C
Two beakers, A and B, each contain an aqueous solution of a different acid at equal concentration and volume. In Beaker A, the diagram shows a large number of ions separated from the acid molecules. In Beaker B, only a small number of ions are shown as separated, with most acid molecules remaining intact.
Deduce which beaker contains the strong acid, and justify your answer using evidence from the diagram. [2]
Deduce which beaker contains the strong acid, and justify your answer using evidence from the diagram. [2]
Solutions
17QuestionEveryday Substances and Their pH ValuesAssessment Practice
6 marks~9 minCriterion D
Farmers apply calcium hydroxide (lime) to acidic soils to raise pH and improve crop yields. Acidic soils (pH below 5.5) reduce nutrient availability and allow toxic metal ions to accumulate.
a
Explain how adding lime raises soil pH and identify two agricultural benefits this produces. [2]
b
Explain two environmental costs associated with the use of lime in agriculture. In your answer, refer to the calcination reaction and the effect of alkaline runoff on aquatic ecosystems. [2]
c
Evaluate the limitation of using pH as the sole indicator of soil quality, and justify whether liming alone is sufficient to ensure long-term soil health. [2]
Solutions
18QuestionDefinition and Real-Life Examples of NeutralizationAssessment Practice
7 marks~11 minCriterion B
A student investigates the hypothesis: "The type of acid used in a neutralization reaction determines the salt produced." Three acids — hydrochloric acid (), sulfuric acid (), and nitric acid () — are each reacted with sodium hydroxide () solution. All solutions are prepared at 0.1 mol/L. The neutralized solutions are evaporated to obtain solid salts.
a
Construct a list of all materials and chemicals required for this experiment. [2]
b
Outline a step-by-step procedure that controls all relevant variables. [2]
c
Identify the independent variable and the dependent variable. [1]
d
Explain how two controlled variables make this experiment a fair test. [2]
Solutions
19QuestionDefinition and Real-Life Examples of NeutralizationAssessment Practice
5 marks~8 minCriterion C
A student investigates the claim that "one antacid tablet completely neutralizes stomach acid." One tablet is added to 100 mL of 0.1 M HCl (simulated stomach acid) and pH is recorded every minute for 10 minutes.
| Time (min) | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| pH | 1.0 | 1.5 | 2.2 | 3.0 | 3.8 | 4.2 | 4.4 | 4.5 | 4.5 | 4.5 | 4.5 |
a
Define complete neutralization, stating the products formed and the expected final pH. [1]
b
Using the data, identify the final equilibrium pH and explain what it indicates about the extent of the reaction. [2]
c
Evaluate the claim that the tablet completely neutralizes the acid. Justify your conclusion using specific evidence from the data. [2]
Solutions
20QuestionDefinition and Real-Life Examples of NeutralizationAssessment Practice
6 marks~9 minCriterion D
A metal processing factory produces 500,000 litres of acidic wastewater daily at pH 3.0. To neutralise the acid before discharge, the factory uses calcium carbonate (limestone):
The process protects a nearby river but produces CO and generates calcium sulfate sludge requiring landfill disposal.
The process protects a nearby river but produces CO and generates calcium sulfate sludge requiring landfill disposal.
a
State one benefit of this neutralisation process for the river ecosystem. [1]
b
Explain how the by-products of this reaction create new environmental problems. [2]
c
Evaluate whether calcium carbonate is a sustainable long-term solution for this factory, comparing it to at least one alternative treatment method. [3]
Solutions