A strong IB Chemistry IA organic chemistry investigation examines a measurable relationship rather than simply making an organic product. Esterification, saponification and fermentation are particularly suitable because each can generate quantitative data using equipment commonly available in school laboratories. The best choice depends on whether your laboratory has facilities such as reflux apparatus, water baths, gas syringes, burettes, pH probes or colorimeters.
This guide explains how to turn these topics into focused research questions, select workable measurements and control significant hazards. The suggested questions are starting points, not titles to copy unchanged. Your final investigation should reflect your equipment, preliminary trials and teacher-approved risk assessment.
What the current IB Chemistry IA requires
Under the Chemistry course first assessed in 2025, the internal assessment is called the scientific investigation. It is an open-ended investigation in which a student gathers and analyses data to answer a formulated research question. The report has a maximum overall word count of 3,000 words, the investigation is allocated 10 hours, and it contributes 20% of the final Chemistry grade at both SL and HL.
The investigation is assessed using four criteria, each worth 6 marks:
| Criterion | What strong organic chemistry investigations demonstrate |
|---|---|
| Research design | A focused question, relevant theory, justified measurements, controlled variables and reproducible methodology |
| Data analysis | Sufficient quantitative data, correct processing, uncertainties and clear interpretation |
| Conclusion | A supported answer to the research question compared with accepted chemical theory or literature |
| Evaluation | Specific methodological limitations, their relative effects and realistic improvements |
The current criteria are different from the older five-criterion system. Personal engagement and communication are no longer separate criteria, although independent decision-making and clear scientific writing still affect the quality of the report. The IB also permits limited collaboration in small groups where appropriate, but every student must submit an individual report and collect unique data relevant to a distinct independent or dependent variable.
Consult the current IB Chemistry subject brief and your teacher's copy of the subject guide before finalizing your plan. RevisionDojo's current IB Chemistry IA guide can help you interpret the criteria, but your teacher remains responsible for approving practical work.
How to choose a feasible organic chemistry investigation
A sophisticated reaction does not automatically produce a strong IA. A simpler reaction with precise measurements, repeated trials and meaningful processing is usually more successful than a complex synthesis that produces only one yield value.
Before committing to an idea, answer these questions:
- Can the independent variable be changed across approximately five sensible values?
- Can the dependent variable be measured quantitatively rather than judged by smell, appearance or foam alone?
- Can important conditions such as temperature, time, concentration and reactant quantity be controlled?
- Can enough repeated measurements be completed within the available laboratory time?
- Does the school have suitable ventilation, heating and waste-disposal arrangements?
- Can the hazards be reduced without undermining the chemistry being investigated?
Run a small preliminary trial before fixing the range. Pilot work reveals whether a reaction is too slow, gas production exceeds the apparatus capacity or a titration endpoint is difficult to distinguish. It also gives you evidence for justifying the range and measurement method in your research design.
Esterification IA ideas
Fischer esterification involves the reversible reaction of a carboxylic acid with an alcohol to form an ester and water:
carboxylic acid + alcohol ⇌ ester + water
It connects organic functional groups with equilibrium, kinetics, catalysis and analytical chemistry. However, simply preparing an ester and reporting its smell is descriptive and does not provide adequate data.
Possible esterification research questions
- How does reaction temperature affect the initial rate of ethyl ethanoate formation under fixed acid-catalysed conditions?
- How does the initial alcohol-to-carboxylic-acid mole ratio affect equilibrium ester yield?
- How does the carbon-chain length of a series of primary alcohols affect esterification rate under otherwise constant conditions?
- How does catalyst concentration affect the rate at which a fixed esterification mixture approaches equilibrium?
The first two are generally more controllable than changing alcohol identity. Different alcohols have different boiling points, solubilities, toxicities and steric properties, creating several simultaneous changes. If you compare a homologous series, acknowledge that chain length is a molecular descriptor rather than the only chemical property changing.
Useful dependent variables include residual carboxylic acid concentration measured by titration, isolated dry ester yield or ester concentration measured using suitable instrumental analysis. Titrating samples removed at defined times can generate a concentration-time graph, but the reaction must be quenched consistently and catalyst acidity must be accounted for. Isolated yield is easier conceptually but can be distorted by transfer losses, incomplete separation and residual water.
Esterification also requires careful hazard control. Alcohols and many esters are flammable, while concentrated ethanoic acid and sulfuric acid are corrosive. The Royal Society of Chemistry's school ester preparation guidance specifies eye protection and controlled heating; an open flame is inappropriate around flammable organic liquids. Reflux, concentrated reagents and separations should only be used when your school has the correct apparatus, ventilation and supervision.
Saponification and soap IA ideas
Saponification is the base hydrolysis of triglyceride esters. A fat or oil reacts with hydroxide ions to form glycerol and salts of fatty acids, which act as soaps. This topic can connect ester hydrolysis with intermolecular forces, solubility, hard-water chemistry and quantitative analysis.
Possible saponification research questions
- How does reaction temperature affect the rate of saponification of one specified vegetable oil?
- How does sodium chloride concentration during salting out affect the recovered dry mass of soap?
- How does the concentration of calcium ions affect the foaming capacity or precipitate formation of a standardized soap solution?
- How does oil type affect experimentally determined saponification value using a consistent back-titration method?
Mass of freshly collected soap is not necessarily a valid yield measurement because samples may retain water, glycerol, sodium chloride or unreacted alkali. Dry samples to a consistent endpoint and explain why mass change between drying periods matters. Avoid claiming that foam height alone measures cleaning effectiveness, since foam stability depends on shaking technique, tube geometry, concentration and dissolved ions.
An investigation of saponification value offers stronger quantitative chemistry but normally requires heating an oil with a known excess of alkali and determining the remaining alkali by back titration. That demands accurate standardization and a suitable blank. It is more technically demanding than comparing soap yield, so complete preliminary trials before selecting it.
The principal hazards are corrosive sodium hydroxide, hot alkaline mixtures and potentially flammable ethanol. The RSC's microscale soap experiment demonstrates how small quantities and a water bath can reduce risk. Newly prepared soap may retain sodium hydroxide and must not be used on skin.
Fermentation IA ideas
Fermentation is biologically mediated, but it can still support a chemistry IA when the focus is reaction rate, molecular structure, concentration or quantitative product analysis. In alcoholic fermentation, yeast converts glucose primarily into ethanol and carbon dioxide:
C6H12O6 → 2C2H5OH + 2CO2
Carbon dioxide volume is usually the most accessible dependent variable. Measuring gas volume at regular intervals allows you to calculate an initial rate from the gradient of an appropriate section of a volume-time graph.
Possible fermentation research questions
- How does glucose concentration affect the initial rate of carbon dioxide production by a fixed yeast suspension?
- How does temperature affect the initial fermentation rate within a teacher-approved range?
- How does pH, maintained with suitable buffers, affect the rate of carbon dioxide production?
- How does carbohydrate identity affect carbon dioxide production under standardized conditions?
Temperature investigations need enough equilibration time for the reaction mixture, not just the surrounding bath, to reach the intended temperature. Sugar-identity investigations are more difficult to interpret because transport into cells and enzyme pathways differ. A concentration investigation is often the cleanest option because it supports discussion of collision frequency, enzyme saturation and osmotic effects.
Use a gas syringe or another calibrated gas-collection system rather than counting bubbles, because bubble size is inconsistent. Check connections for leaks, keep yeast source and suspension age constant, and standardize mixing and acclimatization time. The RSC's fermentation experiment confirms that yeast freshness, temperature and mixing can materially affect results.
Comparing the three main options
| Topic | Accessible measurement | Main difficulty | Important hazards | Best suited equipment |
|---|---|---|---|---|
| Esterification | Titration, concentration or dry yield | Separating reaction rate from equilibrium and product loss | Flammable liquids and corrosive acids | Electric heating, reflux glassware, burette, ventilation |
| Saponification | Back titration, dry mass or standardized soap behavior | Product purity and complete drying | Corrosive alkali and hot mixtures | Water bath, filtration apparatus, burette, balance |
| Fermentation | Carbon dioxide volume against time | Biological variability and gas leaks | Pressure buildup and glassware breakage | Water bath, gas syringe, thermometer or probe |
Fermentation is often the most accessible when advanced organic apparatus is unavailable. Saponification suits laboratories with titration and filtration equipment. Esterification can produce excellent analysis, but only where controlled heating, ventilation and safe handling of corrosive and flammable substances are routine.
Designing data collection and analysis
Use one principal independent variable and define the chemical system in the research question. State how the dependent variable will be measured, including the analytical technique where this adds necessary precision. For example: How does glucose concentration affect the initial rate of carbon dioxide production by baker's yeast at a controlled temperature, as measured using a gas syringe?
Collect repeated measurements at every independent-variable value. Record raw readings with units and instrument uncertainties, then calculate means and an appropriate measure of spread. RevisionDojo's data-analysis guidance explains tables, uncertainty treatment, graphing and error bars.
Processing should answer the question rather than decorate the report. Depending on your design, useful processing might include:
- initial gradients from concentration-time or gas-volume-time graphs
- percentage yield based on the limiting reactant
- propagated measurement uncertainty
- standard deviation across repeated trials
- regression against a theoretically justified model
- an Arrhenius plot when valid rate constants or comparable initial rates are available
Do not force a linear trend onto curved data. Explain anomalies, but retain measured values unless there is a scientifically defensible reason to exclude one. For further models of presentation and evaluation, consult RevisionDojo Chemistry IA exemplars and its guide to designing effective science IA experiments.
Common mistakes to avoid
- Measuring only one final product: This produces too little evidence to establish a relationship.
- Using subjective observations: Odour, texture and foam descriptions can supplement quantitative data but should not replace it.
- Changing several chemical properties together: Comparing unrelated oils, sugars or alcohols creates confounding variables.
- Ignoring purity and recovery: Wet soap mass or poorly separated ester mass is not automatically product yield.
- Writing generic safety statements: Identify each relevant hazard, exposure route, control and disposal method.
- Choosing unavailable analysis: Do not plan chromatography or spectroscopy unless access and calibration are confirmed.
- Making unsupported causal claims: A trend consistent with theory does not prove that all competing explanations were eliminated.
Jojo AI can help you test whether a proposed question clearly identifies variables and a measurement method. It should not invent results, write the submitted investigation or replace your teacher's safety approval.
Conclusion
The most feasible IB Chemistry IA organic chemistry topics are not necessarily the most elaborate syntheses. Esterification provides rich equilibrium and kinetics analysis, saponification supports hydrolysis and titration work, and fermentation offers accessible rate measurements when gas-collection equipment is available. In every case, prioritize a focused question, adequate quantitative data, controlled conditions, realistic uncertainty analysis and specific hazard controls.
Choose the investigation your school can conduct safely and repeatedly, then use pilot trials to refine the range and method. RevisionDojo's Chemistry IA Guide, coursework exemplars and Jojo AI can support planning, while IA Feedback can help identify weaknesses in a completed draft before submission.
Sources and referenced URLs
- IB Chemistry subject brief, first assessment 2025
- IB Chemistry curriculum updates
- Royal Society of Chemistry: making esters from alcohols and acids
- Royal Society of Chemistry: making soaps using castor oil
- Royal Society of Chemistry: fermentation of glucose using yeast
- RevisionDojo IB Chemistry IA Guide
- RevisionDojo Chemistry IA data-analysis guide
- RevisionDojo Chemistry IA examples
- RevisionDojo guide to effective science IA experiments