75 IB Chemistry IA Ideas: Lab Investigation Starters for SL and HL
If you have searched for IB Chemistry IA ideas, Chemistry IA research questions or IB Chemistry lab report topics, you have probably found the same recycled lists: fifteen headline topics, no variables, no measurement detail, and no explanation of why an examiner would reward one and mark down another. This page is the opposite of that.
Below are 75 investigation starters for the IB Chemistry scientific investigation at SL and HL. Each one gives you a chemistry context, the independent variables worth changing, a realistic way to measure the dependent variable, and extensions that lift a familiar practical into an individual investigation. They are deliberately called starters, because the single biggest cause of a disappointing IA mark is not a weak topic — it is a good topic that was never developed into a focused, measurable research question.
- The internally assessed task is the scientific investigation (first assessment 2025 onwards).
- SL and HL have identical internal assessment requirements. There is no separate HL task.
- The report is limited to 3,000 words.
- It is worth 20% of your final subject grade.
- Examiner guidance is explicit that the investigation should not be a straight repetition of a classic school practical — though a prescribed or familiar practical may be adapted and extended into something genuinely your own.
What actually separates a strong IA idea from a weak one
In three decades of supervising IB Chemistry investigations, the pattern in examiner feedback has barely changed. Marks are rarely lost because a student picked an exotic topic and failed. They are lost because the design could not generate data worth analysing. Before you commit to an idea, test it against these six conditions:
- A clearly defined independent variable that you can change across a sensible numerical range — ideally five or more values, not two categories.
- A quantitative dependent variable measured with enough precision that the change you expect is larger than your measurement uncertainty.
- Enough data for meaningful processing: repeated trials, means, uncertainty, and a graph or model that does real work.
- A chemical explanation that goes beyond describing a trend. “Rate increased with temperature” is an observation. Collision frequency, activation energy and the Boltzmann distribution are chemistry.
- A design that is safe, reproducible and realistic with the equipment your school actually has.
- Scope for evaluation: limitations you can name specifically, a distinction between systematic and random uncertainty, and improvements that are more than “use a more accurate balance”.
The research-question framework that works
Almost every strong IB Chemistry research question can be written into this frame, then tightened:
“How does [quantitative independent variable, with its range] affect [quantitative dependent variable] in [defined chemical system], measured using [named method]?”
Once the sentence is written, refine it until concentrations, temperature ranges, chemical identities, the measurement technique and the key controlled variables are all explicit. If a reader cannot roughly reconstruct your method from the research question alone, it is not finished.
- Acids, bases, buffers and titration (1–12)
- Kinetics and rates of reaction (13–24)
- Energetics, calorimetry and thermochemistry (25–32)
- Redox, electrochemistry, corrosion and electrolysis (33–42)
- Colorimetry, spectroscopy and analytical chemistry (43–52)
- Equilibrium, solubility, water and environmental chemistry (53–64)
- Materials, consumer and real-world chemistry (65–75)
Acids, bases, buffers and titration IA ideas (1–12)
These suit students drawn to titration IA ideas, pH, buffers, weak acids, acid–base equilibria and real-world analytical chemistry. Titration is the most accessible route to a genuinely quantitative dataset in most school laboratories — but only when something other than “which sample is more acidic” is being varied.
1. Vitamin C degradation in juice
Chemistry focus: Redox chemistry, food chemistry and reaction kinetics.
Investigation starter: Investigate how storage temperature, light exposure, storage time, oxygen exposure or container type changes the ascorbic acid concentration of orange juice or another vitamin-C-containing drink.
Possible measurement: DCPIP titration, iodometric/redox titration, or a validated colorimetric method; plot concentration against time and, where appropriate, test kinetic models.
Variants and extensions: Compare fresh with packaged juice; compare juice with a vitamin C tablet solution or a cosmetic vitamin C serum; estimate a rate constant at several temperatures for an HL-style extension.
2. Acidity of fruit juices
Chemistry focus: Acid–base chemistry and titration.
Investigation starter: Instead of asking which juice is most acidic, vary dilution, storage time, temperature or degree of ripeness and measure total titratable acidity.
Possible measurement: Standardised NaOH titration, pH measurement and uncertainty analysis.
Variants and extensions: Compare pH with titratable acidity and explain why they diverge; investigate citric-acid-rich versus malic-acid-rich juices; study how heating affects titratable acidity.
3. Effect of temperature on vinegar acidity
Chemistry focus: Weak acids, equilibrium and acid–base titration.
Investigation starter: Investigate whether prolonged heating or storage temperature changes the apparent ethanoic acid concentration of vinegar.
Possible measurement: NaOH titration with a suitable indicator or pH probe.
Variants and extensions: Compare vinegar types; control mass loss to isolate evaporation effects; distinguish concentration change from chemical decomposition.
4. Commercial antacid neutralising capacity
Chemistry focus: Stoichiometry, acid–base reactions and pharmaceutical chemistry.
Investigation starter: Investigate how antacid mass, active ingredient, particle size or contact time affects the amount of acid neutralised.
Possible measurement: Back titration — react the antacid with excess standardised HCl, then titrate the remaining acid with NaOH.
Variants and extensions: Compare CaCO3-, Mg(OH)2– and mixed antacids; calculate acid-neutralising capacity per gram or per stated dose.
5. Antacid reaction rate and particle size
Chemistry focus: Collision theory and acid–base kinetics.
Investigation starter: Change the particle size or surface area of an antacid while keeping mass constant, and measure how quickly it reacts with acid.
Possible measurement: Gas-volume measurement for carbonate antacids, mass-loss method or pH probe.
Variants and extensions: Compare whole, crushed and powdered tablets; use initial rate rather than total reaction time.
6. Buffer capacity of drinks
Chemistry focus: Buffers, weak acids and bases, equilibrium.
Investigation starter: Investigate how drink composition, dilution or temperature affects resistance to pH change.
Possible measurement: Add standardised strong acid or base in measured increments while recording pH.
Variants and extensions: Compare milk, sports drinks and fruit juices; report the amount of acid or base needed for a fixed pH change rather than comparing initial pH.
7. Buffer concentration and buffer capacity
Chemistry focus: Buffer systems and equilibrium.
Investigation starter: Prepare an ethanoic acid/ethanoate or other suitable buffer and vary total buffer concentration while holding the acid:base ratio constant.
Possible measurement: pH probe with incremental addition of HCl or NaOH.
Variants and extensions: Compare experimental pH with Henderson–Hasselbalch predictions where appropriate; investigate dilution or temperature effects.
8. Acid concentration and titration-curve shape
Chemistry focus: Acid–base equilibria and titration curves.
Investigation starter: Vary the initial concentration of a weak acid and investigate changes in the titration curve, the buffer region or the equivalence-point pH.
Possible measurement: High-resolution pH probe or data logger during titration with standardised NaOH.
Variants and extensions: Compare strong and weak monoprotic acids; use first-derivative plots to locate equivalence points objectively.
9. Weak-acid identity and neutralisation behaviour
Chemistry focus: Acid strength, pKa and equilibrium.
Investigation starter: Compare structurally related weak acids at matched concentrations, investigating pH, buffer behaviour or titration-curve features.
Possible measurement: pH probe and titration.
Variants and extensions: Use ethanoic acid and other safe carboxylic acids available in school; relate the results to molecular structure and Ka.
10. Carbon dioxide and acidity of water
Chemistry focus: Acid–base equilibrium and environmental chemistry.
Investigation starter: Investigate how contact time with CO2, gas flow time or temperature changes the pH or acidity of water.
Possible measurement: pH probe; optionally titrate the absorbed acidity.
Variants and extensions: Model ocean acidification carefully under safe laboratory conditions; compare distilled water with buffered or mineral-containing water.
11. Temperature and pH of a buffer
Chemistry focus: Equilibrium and thermodynamics.
Investigation starter: Investigate how the measured pH of a defined buffer changes with temperature.
Possible measurement: Calibrated pH probe and thermostated water bath.
Variants and extensions: Compare buffer systems; discuss the temperature dependence of dissociation equilibria and of electrode calibration itself.
12. Acid–base indicator behaviour
Chemistry focus: Equilibrium, molecular structure and spectroscopy.
Investigation starter: Investigate how pH affects the absorbance or colour ratio of an acid–base indicator.
Possible measurement: Colorimeter, spectrophotometer or calibrated digital image analysis.
Variants and extensions: Determine an approximate transition range or pKa; compare two indicators; study temperature effects if equipment allows.
Kinetics and rates of reaction IA ideas (13–24)
Kinetics investigations are popular for good reason: they naturally produce time-series data and can be developed through concentration, temperature, surface area or catalyst variables. They also give you the richest options for processing — initial rates, orders of reaction, linearisation and Arrhenius analysis.
13. Sodium thiosulfate and hydrochloric acid
Chemistry focus: Reaction kinetics and collision theory.
Investigation starter: Adapt the classic disappearing-cross experiment by varying temperature or reactant concentration quantitatively.
Possible measurement: Time to a defined turbidity endpoint, or a light sensor or colorimeter if available.
Variants and extensions: Use initial-rate proxies; compare the manual endpoint with light-sensor data; test how ionic strength or temperature affects rate.
14. Magnesium and hydrochloric acid
Chemistry focus: Kinetics, metals and acids.
Investigation starter: Vary HCl concentration, temperature or magnesium surface area and measure hydrogen production.
Possible measurement: Gas syringe, pressure sensor or mass-loss method.
Variants and extensions: Calculate initial rates from gas-volume–time curves; compare ribbon preparation methods; investigate the effect of removing the oxide layer.
15. Effervescent tablet kinetics
Chemistry focus: Acid–carbonate reactions and pharmaceutical chemistry.
Investigation starter: Vary water temperature, tablet surface area or solution composition and quantify CO2 production.
Possible measurement: Gas syringe, pressure sensor or mass loss against time.
Variants and extensions: Construct an Arrhenius-style analysis using rate constants at several temperatures; compare whole with powdered tablets.
16. Food dye bleaching by hypochlorite
Chemistry focus: Kinetics, oxidation and analytical chemistry.
Investigation starter: Vary bleach concentration, dye concentration or temperature and monitor the loss of colour.
Possible measurement: Colorimeter or spectrophotometer, giving absorbance–time data.
Variants and extensions: Determine pseudo-order kinetics under excess-reagent conditions; compare dyes; investigate activation energy.
17. Crystal violet fading
Chemistry focus: Kinetics and spectrophotometry.
Investigation starter: Where permitted and safely supervised, vary hydroxide concentration and monitor the fading of crystal violet.
Possible measurement: Spectrophotometer or colorimeter.
Variants and extensions: Determine reaction order under pseudo-first-order conditions; examine temperature dependence.
18. Hydrogen peroxide decomposition
Chemistry focus: Kinetics, catalysis and redox chemistry.
Investigation starter: Vary catalyst concentration, temperature or pH and monitor oxygen evolution.
Possible measurement: Gas syringe, oxygen sensor or pressure sensor.
Variants and extensions: Compare safe catalysts such as iodide or suitable metal oxides; calculate initial rate or rate constant.
19. Catalytic decomposition using manganese(IV) oxide
Chemistry focus: Heterogeneous catalysis and kinetics.
Investigation starter: Investigate how catalyst mass or particle size affects the rate of hydrogen peroxide decomposition.
Possible measurement: Oxygen volume or pressure against time.
Variants and extensions: Separate catalyst surface area from catalyst mass; discuss why a catalyst changes rate but not the overall stoichiometric yield.
20. Iodide-catalysed hydrogen peroxide reaction
Chemistry focus: Homogeneous catalysis and kinetics.
Investigation starter: Vary iodide concentration or temperature while keeping other reactants controlled.
Possible measurement: Gas evolution or an appropriate timed analytical method.
Variants and extensions: Determine an empirical rate relationship; compare catalysed and uncatalysed systems.
21. Temperature and reaction rate: an Arrhenius investigation
Chemistry focus: Activation energy and kinetics.
Investigation starter: Choose a safe reaction that can be monitored reproducibly and run it over at least five temperatures.
Possible measurement: Rate constant, or a carefully defined initial-rate proxy.
Variants and extensions: Plot ln(k) against 1/T to estimate activation energy; dye bleaching and selected clock reactions work well.
22. Iodine clock variants
Chemistry focus: Kinetics and redox reactions.
Investigation starter: Vary one reactant concentration while keeping others constant and record induction time to a defined colour change.
Possible measurement: Timing to the starch–iodine endpoint; a data logger or light sensor improves objectivity.
Variants and extensions: Determine reaction order empirically; examine the temperature effect; assess the limitations of using 1/time as a rate proxy.
23. Surface area and carbonate–acid reaction
Chemistry focus: Collision theory and gas evolution.
Investigation starter: Use equal masses of calcium carbonate with controlled particle-size ranges and react with acid.
Possible measurement: CO2 gas volume or mass loss versus time.
Variants and extensions: Sieve particle sizes if available; calculate initial rate while keeping total moles constant.
24. Ionic strength and reaction rate
Chemistry focus: Kinetics and ionic reactions.
Investigation starter: For an appropriate school-safe ionic reaction, vary inert electrolyte concentration while reactant concentrations remain fixed.
Possible measurement: Time-based or spectrophotometric rate measurement.
Variants and extensions: A more advanced HL-style starter that opens up discussion of ionic interactions and rigorous experimental control.
Energetics, calorimetry and thermochemistry IA ideas (25–32)
Calorimetry is accessible in almost every school laboratory, but the strongest designs go beyond a single enthalpy measurement and investigate a systematic variable. Heat loss is the dominant systematic error here, which makes these investigations unusually rich for evaluation marks — provided you quantify it rather than just mention it.
25. Enthalpy of combustion across an alcohol homologous series
Chemistry focus: Energetics, homologous series and intermolecular chemistry.
Investigation starter: Investigate how carbon chain length affects the experimentally measured molar enthalpy of combustion.
Possible measurement: Simple or improved calorimetry using mass of fuel burned and water temperature change.
Variants and extensions: Compare methanol, ethanol, propan-1-ol and butan-1-ol where school safety rules allow; analyse systematic heat loss as a function of chain length.
26. Alcohol structure and combustion
Chemistry focus: Structure–property relationships and energetics.
Investigation starter: Compare isomeric alcohols, or primary versus secondary alcohols, where suitable reagents are available.
Possible measurement: Calorimetry.
Variants and extensions: Relate differences to molecular structure while carefully discussing the large heat-loss uncertainties that may swamp them.
27. Enthalpy of neutralisation: strong versus weak acid
Chemistry focus: Energetics and acid dissociation.
Investigation starter: Compare temperature change or molar enthalpy when NaOH neutralises acids of different strengths.
Possible measurement: Insulated calorimeter with temperature probe.
Variants and extensions: Vary acid identity at matched concentration; compare strong/strong with weak/strong systems and explain the energy consumed in ionisation.
28. Concentration and measured enthalpy of neutralisation
Chemistry focus: Calorimetry and systematic error.
Investigation starter: Investigate how reactant concentration influences the experimentally determined enthalpy of neutralisation.
Possible measurement: Temperature probe or data logger with calorimetry.
Variants and extensions: Excellent vehicle for discussing heat loss, the heat capacity of the apparatus, and extrapolation back to mixing time.
29. Enthalpy of solution of ionic solids
Chemistry focus: Lattice enthalpy, hydration and dissolution energetics.
Investigation starter: Compare the temperature change when equal molar amounts of different safe salts dissolve.
Possible measurement: Calorimetry.
Variants and extensions: Alternatively vary solute concentration for one salt; compare exothermic CaCl2 with endothermic salts approved by your school.
30. Hydration state and enthalpy of solution
Chemistry focus: Hydrates, lattice and hydration effects, Hess cycles.
Investigation starter: Compare an anhydrous salt with its hydrated form where both are safely available.
Possible measurement: Calorimetry.
Variants and extensions: Use the difference between measured enthalpies as part of an indirect energetic calculation via Hess’s law.
31. Heat capacity of salt solutions
Chemistry focus: Thermal properties and solution chemistry.
Investigation starter: Investigate how solute concentration affects the apparent specific heat capacity of an aqueous solution.
Possible measurement: Electrical heating with a temperature probe and measured energy input.
Variants and extensions: Compare NaCl or another safe solute over a concentration range; account for heat losses and calorimeter heat capacity.
32. Instant hot and cold pack chemistry
Chemistry focus: Enthalpy of dissolution and real-world chemistry.
Investigation starter: Investigate how concentration, solute mass or salt identity affects maximum temperature change and energy released or absorbed per gram.
Possible measurement: Calorimetry.
Variants and extensions: Frame the question around formulating a reusable or single-use pack; distinguish total temperature change from molar enthalpy.
Redox, electrochemistry, corrosion and electrolysis IA ideas (33–42)
These starters connect redox chemistry with electrolysis, corrosion, electrochemical cells and quantitative titration. They are among the best options for a comparison between measured data and theoretical prediction — Faraday’s law and the Nernst relationship both give you something concrete to test against.
33. Copper electroplating and current
Chemistry focus: Electrolysis and Faraday’s law.
Investigation starter: Vary current while electroplating copper for a fixed time and measure the mass deposited.
Possible measurement: Analytical balance, ammeter and timed electrolysis.
Variants and extensions: Compare experimental deposition with Faraday-law predictions; investigate current efficiency and where it is lost.
34. Copper electroplating and time
Chemistry focus: Electrolysis and quantitative stoichiometry.
Investigation starter: Keep current constant and vary electrolysis time.
Possible measurement: Mass change of the electrode.
Variants and extensions: Test linearity between charge passed and copper mass; include uncertainty from drying protocol and balance precision.
35. Electrolyte concentration and copper deposition
Chemistry focus: Electrochemistry and conductivity.
Investigation starter: Vary CuSO4 concentration while controlling electrode area, current or voltage, and time.
Possible measurement: Mass change, current, and possibly conductivity.
Variants and extensions: Discuss whether concentration affects current efficiency or cell resistance under your chosen control conditions.
36. Cell potential and ion concentration
Chemistry focus: Electrochemical cells and the Nernst relationship.
Investigation starter: Construct a suitable galvanic cell and vary one ion concentration.
Possible measurement: High-impedance voltmeter.
Variants and extensions: Plot cell potential against log concentration; compare the experimental gradient with theoretical prediction.
37. Temperature and electrochemical cell potential
Chemistry focus: Electrochemistry and thermodynamics.
Investigation starter: Measure the emf of a defined cell at several temperatures.
Possible measurement: Voltmeter and controlled water bath.
Variants and extensions: An advanced investigation requiring careful temperature equilibration; interpret thermodynamically but cautiously.
38. Corrosion rate and sodium chloride concentration
Chemistry focus: Redox chemistry and environmental corrosion.
Investigation starter: Expose iron or steel samples to controlled salt concentrations.
Possible measurement: Mass change after cleaning and drying, dissolved iron analysis, or an electrochemical method if available.
Variants and extensions: Use identical metal pieces and identical surface preparation; consider oxygen availability and exposure duration as controlled variables.
39. Corrosion and pH
Chemistry focus: Redox, acids and corrosion.
Investigation starter: Investigate how solution pH changes the corrosion behaviour of iron.
Possible measurement: Mass change or quantitative iron-ion analysis.
Variants and extensions: Use buffered systems where possible to hold pH steady; avoid simply comparing unrelated household liquids.
40. Protective coatings and corrosion
Chemistry focus: Materials chemistry and redox.
Investigation starter: Compare defined coating thicknesses or coating types on identical iron samples.
Possible measurement: Mass change or corrosion-product analysis.
Variants and extensions: Vary one coating parameter quantitatively — thickness, number of layers — rather than ranking commercial products.
41. Bleach concentration by iodometric titration
Chemistry focus: Redox titration and consumer chemistry.
Investigation starter: Determine available hypochlorite concentration in bleach and investigate degradation with storage time, temperature or light.
Possible measurement: Iodometric titration with standardised sodium thiosulfate.
Variants and extensions: Model concentration loss over time and compare storage conditions — one of the strongest extension routes on this list.
42. Hydrogen peroxide concentration during storage
Chemistry focus: Redox chemistry and decomposition.
Investigation starter: Investigate how temperature, light or container type affects H2O2 concentration over time.
Possible measurement: Permanganate titration or another school-approved quantitative redox method.
Variants and extensions: Compare opaque with transparent storage; determine the rate of decomposition rather than only the final concentration.
Colorimetry, spectroscopy and analytical chemistry IA ideas (43–52)
Colorimetry and spectrophotometry produce some of the highest-quality quantitative datasets available to IB students. Calibration, Beer–Lambert behaviour, linear range and instrument limitations all give you substantial material for analysis and evaluation — but a calibration curve on its own is not an investigation. You still need a variable.
43. Food dye concentration using Beer–Lambert calibration
Chemistry focus: Analytical chemistry and spectroscopy.
Investigation starter: Construct a calibration curve and use it to determine dye concentration in a beverage or prepared mixture.
Possible measurement: Colorimeter or spectrophotometer.
Variants and extensions: For IA depth, add a variable such as storage time, light exposure, pH or bleaching-agent concentration.
44. Light-induced fading of food dyes
Chemistry focus: Photochemistry and kinetics.
Investigation starter: Expose dye solutions to controlled light intensities or exposure times.
Possible measurement: Absorbance measured at regular intervals.
Variants and extensions: Include a dark control; vary distance from the lamp while controlling temperature, which is the usual confounder here.
45. pH and colour of anthocyanins
Chemistry focus: Acid–base equilibria and molecular structure.
Investigation starter: Investigate how pH changes the absorption spectrum or colour intensity of an anthocyanin extract.
Possible measurement: Spectrophotometer, colorimeter or standardised digital-image analysis.
Variants and extensions: Use red cabbage or berry extracts; quantify wavelength and absorbance changes rather than describing colours subjectively.
46. Temperature and anthocyanin stability
Chemistry focus: Food chemistry, kinetics and molecular stability.
Investigation starter: Store a standardised anthocyanin solution at different temperatures and measure pigment loss.
Possible measurement: Absorbance over time.
Variants and extensions: Compare pH conditions; determine apparent degradation rate constants and, if the data support it, an activation energy.
47. Metal-ion complex concentration by colorimetry
Chemistry focus: Transition metals, complex ions and the Beer–Lambert law.
Investigation starter: Prepare a series of known complex concentrations and investigate absorbance relationships.
Possible measurement: Colorimeter or spectrophotometer.
Variants and extensions: Use a school-approved transition-metal complex; extend to equilibrium composition or ligand concentration effects.
48. Iron content in fortified foods
Chemistry focus: Analytical chemistry and complex formation.
Investigation starter: Extract iron from a suitable fortified product and determine its concentration using a coloured complex.
Possible measurement: Colorimetric calibration curve.
Variants and extensions: Compare stated with measured values; vary extraction conditions such as time, acid concentration or pH rather than just comparing brands.
49. Copper concentration in water
Chemistry focus: Analytical and environmental chemistry.
Investigation starter: Use calibration standards to determine Cu2+ concentration in prepared or teacher-supplied samples.
Possible measurement: Colorimeter or spectrophotometer.
Variants and extensions: Investigate adsorption or removal by a material, or precipitation conditions, to give yourself a genuine independent variable.
50. Effect of solvent composition on absorption
Chemistry focus: Molecular interactions and spectroscopy.
Investigation starter: Investigate how solvent polarity or solvent composition affects the absorbance maximum or intensity of a suitable dye.
Possible measurement: Spectrophotometer.
Variants and extensions: Best suited to well-equipped HL laboratories; select solvents strictly according to school safety rules.
51. Equilibrium constant of a coloured complex
Chemistry focus: Chemical equilibrium and spectrophotometry.
Investigation starter: Prepare mixtures with different initial concentrations and use absorbance to estimate equilibrium composition.
Possible measurement: Spectrophotometer with a calibration relationship.
Variants and extensions: A strong HL-style starter, provided the chosen equilibrium and its assumptions are stated and justified.
52. Digital image colorimetry as a low-cost analytical method
Chemistry focus: Analytical chemistry and method validation.
Investigation starter: Create standards of a coloured solution and relate RGB or HSV intensity to concentration.
Possible measurement: Smartphone camera under fixed lighting, plus image-analysis software.
Variants and extensions: Compare a smartphone-derived calibration with a laboratory colorimeter; evaluate precision, sensor saturation and lighting control.
Equilibrium, solubility, water and environmental chemistry IA ideas (53–64)
Environmental and equilibrium investigations work best when they use a well-controlled chemical model rather than uncontrolled samples from different brands or locations. “River water from three sites” sounds impressive and almost always produces data you cannot explain.
53. Solubility and temperature
Chemistry focus: Equilibrium and dissolution.
Investigation starter: Measure the solubility of a suitable solid across a controlled temperature range.
Possible measurement: Mass of solute required for saturation, or a crystallisation method.
Variants and extensions: Construct a solubility curve; compare with literature data and discuss supersaturation as a source of error.
54. Common-ion effect on solubility
Chemistry focus: Solubility equilibria and Le Châtelier’s principle.
Investigation starter: Investigate how the concentration of a common ion affects the solubility of a suitable sparingly soluble salt.
Possible measurement: Titration, conductivity or another quantitative concentration method.
Variants and extensions: An advanced starter requiring careful chemical choice and waste-handling planning.
55. Temperature and equilibrium position
Chemistry focus: Chemical equilibrium and thermodynamics.
Investigation starter: Use a safe reversible system with a measurable colour or concentration change and vary temperature.
Possible measurement: Spectrophotometry or colorimetry.
Variants and extensions: Estimate an equilibrium-related quantity at several temperatures; select the system with teacher approval.
56. Reactant concentration and equilibrium composition
Chemistry focus: Equilibrium and Le Châtelier’s principle.
Investigation starter: Vary initial concentration in a measurable equilibrium system.
Possible measurement: Spectrophotometry or titration.
Variants and extensions: Avoid purely visual observations; calculate equilibrium concentrations or an equilibrium constant where the chemistry allows.
57. Water hardness by EDTA titration
Chemistry focus: Complexometric titration and environmental chemistry.
Investigation starter: Determine total hardness of water and investigate a controlled treatment variable.
Possible measurement: EDTA titration with a suitable indicator and buffer.
Variants and extensions: Compare before and after boiling; vary boiling time; use prepared hardness standards; report CaCO3-equivalent hardness.
58. Boiling time and temporary hardness
Chemistry focus: Carbonate equilibria and water chemistry.
Investigation starter: Boil hard-water samples for different times under controlled conditions.
Possible measurement: EDTA titration before and after treatment.
Variants and extensions: Track the decrease in hardness against time; control evaporation by restoring mass or volume before titrating.
59. Ion-exchange water softening
Chemistry focus: Ion exchange and environmental chemistry.
Investigation starter: Investigate how contact time or resin mass affects removal of hardness ions.
Possible measurement: EDTA titration or conductivity with suitable controls.
Variants and extensions: Compare breakthrough behaviour across repeated uses of a small resin column if school equipment allows.
60. Conductivity and electrolyte concentration
Chemistry focus: Ions in solution and electrical conductivity.
Investigation starter: Prepare a concentration series for an electrolyte and measure conductivity.
Possible measurement: Conductivity probe.
Variants and extensions: Compare strong and weak electrolytes; calculate molar conductivity; investigate dilution behaviour and where linearity breaks down.
61. Conductivity during neutralisation
Chemistry focus: Ionic reactions and titration.
Investigation starter: Follow conductivity as an acid is titrated with a base.
Possible measurement: Conductivity probe or data logger.
Variants and extensions: Compare strong acid–strong base with weak acid–strong base; locate the equivalence region from the conductivity trend and explain the shape ionically.
62. Adsorption of dye by activated carbon
Chemistry focus: Surface chemistry and environmental remediation.
Investigation starter: Vary activated carbon mass, contact time, pH or initial dye concentration.
Possible measurement: Colorimeter or spectrophotometer before and after treatment.
Variants and extensions: Calculate percentage removal and adsorption capacity; more advanced work can explore adsorption models without overcomplicating the report.
63. Removal of metal ions by an adsorbent
Chemistry focus: Environmental and analytical chemistry.
Investigation starter: Use teacher-approved metal-ion solutions and a safe adsorbent; vary adsorbent mass or contact time.
Possible measurement: Colorimetry or titration depending on the ion.
Variants and extensions: Compare natural and commercial adsorbents only if the chemical measurement stays central to the question.
64. Precipitation efficiency and pH
Chemistry focus: Solubility equilibria and separation chemistry.
Investigation starter: Investigate how pH affects precipitation of a teacher-approved metal hydroxide or comparable system.
Possible measurement: Filter, dry and weigh the precipitate, or determine residual ion concentration.
Variants and extensions: Discuss competing equilibria and incomplete precipitation; requires careful safety and waste planning.
Materials, consumer and real-world Chemistry IA ideas (65–75)
Real-world contexts make an investigation engaging, and they help you write a genuine personal-engagement rationale. But the chemistry must remain central: a numerical variable and an objective chemical measurement always beat a subjective product ranking.
65. Calcium carbonate content of eggshell
Chemistry focus: Stoichiometry, acids and carbonate chemistry.
Investigation starter: Determine CaCO3 content and investigate shell treatment, source or heating condition.
Possible measurement: Back titration after reaction with excess acid.
Variants and extensions: For a stronger IA, vary a controlled treatment such as heating temperature or time rather than merely comparing eggs.
66. Calcium carbonate content of chalk or tablets
Chemistry focus: Stoichiometry and acid–base chemistry.
Investigation starter: Determine carbonate purity, or investigate how processing affects measured carbonate content.
Possible measurement: Back titration or CO2 measurement.
Variants and extensions: Compare two analytical methods on the same sample; investigate particle size for rate while keeping composition constant.
67. Descaling efficiency of weak acids
Chemistry focus: Acid–carbonate chemistry and household chemistry.
Investigation starter: Investigate how acid concentration or temperature affects dissolution of a standardised CaCO3 deposit.
Possible measurement: Mass loss, CO2 production or residual-acid titration.
Variants and extensions: Compare citric and ethanoic acid only if concentrations and acid equivalents are carefully matched.
68. Temperature and browning-related acidity or reducing chemistry
Chemistry focus: Food chemistry and oxidation–reduction.
Investigation starter: Investigate a clearly defined chemical marker in a heated food model rather than subjective colour alone.
Possible measurement: Colorimetry, pH or a validated titration method depending on the system.
Variants and extensions: A higher-complexity starter that needs pilot testing and a specific chemical mechanism before you commit.
69. Soap and hard water
Chemistry focus: Ions, precipitation and surfactant chemistry.
Investigation starter: Investigate how Ca2+ concentration affects soap performance using a quantitative endpoint.
Possible measurement: Volume of standardised soap solution needed for a persistent lather, turbidity, or precipitate mass.
Variants and extensions: Use prepared hardness solutions rather than uncontrolled tap water; compare soap with a synthetic detergent as an extension.
70. Detergent and water hardness
Chemistry focus: Surfactants and solution chemistry.
Investigation starter: Investigate how hardness-ion concentration affects a measurable property of a detergent system.
Possible measurement: Surface-tension method, foam persistence under standardised agitation, or turbidity where appropriate.
Variants and extensions: Needs careful method validation; avoid a purely subjective “cleaning power” comparison.
71. Salt concentration and freezing point
Chemistry focus: Colligative properties and solutions.
Investigation starter: Investigate how the molality of a solute affects freezing-point depression.
Possible measurement: Temperature probe and a controlled cooling curve.
Variants and extensions: Compare the experimental gradient with theoretical prediction; account explicitly for supercooling.
72. Sugar concentration and freezing point
Chemistry focus: Colligative properties and molecular solutions.
Investigation starter: Prepare sucrose solutions of known molality and measure freezing behaviour.
Possible measurement: Temperature probe or data logger.
Variants and extensions: Compare ionic and non-ionic solutes at equal molality as an extension, keeping the core research question focused.
73. Evaporation rate and intermolecular forces
Chemistry focus: Intermolecular forces and volatility.
Investigation starter: Investigate evaporation of a homologous series, or of aqueous alcohol mixtures, under controlled conditions.
Possible measurement: Mass loss against time at fixed surface area and temperature.
Variants and extensions: Relate rate to molecular structure and vapour pressure; strict ventilation and safety requirements apply.
74. Dissolution rate and temperature
Chemistry focus: Particle interactions, dissolution kinetics and solution chemistry.
Investigation starter: Investigate how temperature affects the dissolution rate of a selected safe solid.
Possible measurement: Conductivity, refractive index, or a mass/visual endpoint only if quantitatively validated.
Variants and extensions: Far stronger than a simple “time to disappear” experiment when concentration can be monitored continuously.
75. Comparing analytical methods for the same chemical quantity
Chemistry focus: Method validation, uncertainty and analytical chemistry.
Investigation starter: Measure one quantity — vitamin C, acidity, hardness or concentration — using two independent school-appropriate methods.
Possible measurement: Titration versus colorimetry; conductivity versus titration where chemically valid.
Variants and extensions: Frame the research question around accuracy, precision, calibration range or systematic bias. A genuinely strong investigation when both methods are quantitative and you can explain the chemistry behind their disagreement.
From an IA idea to a Chemistry research question
A broad topic such as “vitamin C” or “corrosion” is not yet a research question. The next step is to select one independent variable and one quantitative response, then define the chemical system and the method. Here is the same idea at three stages of development:
| Stage | Example |
|---|---|
| Too broad | How does temperature affect vitamin C? |
| Better starter | How does storage temperature affect the concentration of ascorbic acid in orange juice over time, measured by redox titration? |
| Properly defined | How does storage at 10, 20, 30, 40 and 50 °C affect the degradation rate of ascorbic acid in a standardised orange-juice sample over 120 minutes, determined by DCPIP titration? |
Eight questions to ask before you commit to an experiment
- Can I vary the independent variable across at least five sensible values?
- Can I measure the dependent variable quantitatively and with sufficient precision?
- Can I repeat measurements and estimate uncertainty properly?
- Is the chemistry behind the expected trend substantial enough to discuss in depth?
- Can the experiment be completed safely with my school’s approved chemicals and equipment?
- Can I control the important variables, rather than comparing many uncontrolled commercial products?
- Will the resulting data support an appropriate graph, mathematical treatment or comparison with theory?
- Is this my own developed question, rather than a copy of an IA found online?
Data-analysis approaches that earn marks
Processing is where competent IAs become distinguished ones. Choose the treatments your data can genuinely support:
- Mean, standard deviation and uncertainty from repeated trials.
- Percentage uncertainty and propagation of uncertainty through calculations.
- Calibration curves and interpolation for analytical chemistry, with the linear range stated.
- Initial-rate calculations from concentration–time, gas-volume–time or absorbance–time data.
- Linearisation or model comparison for kinetic data, where chemically justified.
- Arrhenius plots for temperature-dependent rate constants.
- Comparison of experimental with theoretical or literature values, including percentage error where meaningful.
- Interpretation of gradient and intercept — what they mean chemically — rather than reporting a correlation coefficient alone.
- Residuals, or a discussion of whether the fitted model actually describes the data.
Common weaknesses in Chemistry IA and lab report topics
Every one of these appears repeatedly in weaker reports. If your plan contains any of them, revise before you start collecting data — not after:
- Comparing brands only, with no controlled quantitative independent variable.
- Subjective endpoints such as “cleanest”, “best”, “most colour” or “finished fizzing”.
- Too few data points, or a single trial per condition.
- Choosing a biological experiment in which the chemistry is secondary.
- Changing several variables at the same time.
- Using a sophisticated instrument without understanding its calibration, its limitations or what it actually measures.
- Repeating a classic school practical without adapting it into an individual investigation.
- Leaving safety, ethics and waste disposal as an afterthought rather than part of the design.
IB Chemistry IA: frequently asked questions
What is a good IB Chemistry IA idea?
A good IB Chemistry IA idea has a quantitative independent variable you can change across at least five values, a dependent variable you can measure precisely enough to detect that change, and underlying chemistry rich enough to explain rather than merely describe. It must also be safe and achievable with your school’s equipment. Topic novelty matters far less than design quality — an adapted titration or kinetics experiment with a well-controlled variable will outperform an exotic idea that produces unusable data.
Are the Chemistry IA requirements the same for SL and HL?
Yes. Under the current Chemistry course, first assessment 2025, SL and HL students complete the same internally assessed scientific investigation, subject to the same 3,000-word limit, and it carries 20% of the final subject grade at both levels. HL students often choose topics that draw on HL-only content, but there is no additional or separate HL requirement.
How do I turn a Chemistry lab idea into a research question?
Use the frame: “How does [quantitative independent variable, with its range] affect [quantitative dependent variable] in [defined chemical system], measured using [named method]?” Then tighten it until the concentrations, temperature range, chemical identities and measurement technique are all explicit. A reader should be able to sketch your method from the research question alone.
How many values should I use for my independent variable?
Aim for at least five values spread across a range wide enough that the change in your dependent variable is clearly larger than your measurement uncertainty, with three to five repeat trials at each value. Fewer than five values makes it difficult to identify a trend or fit a model with any confidence, and single trials leave you with no way to estimate random uncertainty.
What makes a Chemistry IA experiment too simple?
An experiment is too simple when it reproduces a standard school practical without adaptation, when the independent variable is categorical rather than numerical, or when the outcome is known in advance and requires no real analysis. Comparing two commercial products, or timing how long a tablet takes to dissolve in hot and cold water, will not generate enough data or enough chemistry to reward.
Can I use titration for my IB Chemistry IA?
Yes, and titration is one of the most reliable routes to precise quantitative data in a school laboratory. The requirement is that something is genuinely varied. Back titration for antacid capacity, iodometric titration of bleach as it degrades, or EDTA titration of hardness before and after a controlled treatment all give you a numerical independent variable and a defensible measurement.
Can I use colorimetry or a spectrophotometer in a Chemistry IA?
Yes. Colorimetry and spectrophotometry produce excellent absorbance–time and absorbance–concentration datasets and let you build a calibration curve based on the Beer–Lambert law. Make sure you understand the linear range, the effect of wavelength selection, and the instrument’s limitations — examiners reward students who discuss calibration critically rather than treating the reading as absolute truth.
Can I do an IB Chemistry IA at home?
Only with your teacher’s explicit approval, and never with hazardous chemicals or improvised equipment. Where laboratory access is limited, discuss a database-based investigation or a simulation-based investigation with your teacher — both are legitimate routes under the current guide, and both still require a focused research question, real data processing and a genuine chemical explanation.
How should I analyse uncertainty in a Chemistry lab report?
Start from the instrument uncertainty of every measuring device you use, combine repeated-trial scatter into a standard deviation, and propagate uncertainties through your calculations to reach an uncertainty on your final quantity. Then separate random from systematic effects: random uncertainty shows up as scatter around your trend, while systematic error shifts the whole trend — often visible in an unexpected intercept. Discussing what your gradient and intercept mean chemically is worth more than quoting a correlation coefficient.
Working on your Chemistry IA now?
iBLaurel offers one-to-one IB Chemistry tuition for SL and HL students, including focused support on turning an investigation idea into a defensible research question, designing for data quality, and analysing uncertainty properly. We do not write or complete internally assessed work — we teach students to plan, analyse and evaluate their own investigations to the standard the criteria reward.
Sources consulted
- International Baccalaureate. Chemistry guide, first assessment 2025 (published February 2023; subsequent guidance applies to the current course).
- International Baccalaureate. Chemistry Internal Assessment — Scientific Investigation, Examiner Instructions 2026.
- International Baccalaureate. Chemistry in the Diploma Programme, updated 6 March 2026.
This page is reviewed against current IB documentation at least once per academic year. Last reviewed August 2026. Students should always confirm current requirements with their own teacher and school, as IB guidance is updated periodically.