10 free IGCSE Chemistry Organic Chemistry questions written in the style of Cambridge Chemistry papers: 3 multiple-choice and 7 structured, each with its answer and mark scheme. 4 of them are A* challenge questions, built to catch the mistakes strong students still make.
This topic covers Formulae, functional groups & naming, Alkanes & alkenes, Alcohols & carboxylic acids, Polymers. Work through the questions below, then generate a full Organic Chemistry paper with a fresh set every time.
Generate a full Organic Chemistry paper →Ethanol is made by fermentation and by the catalytic addition of steam to ethene.
Which row is correct?
| fermentation | addition of steam | |
|---|---|---|
| A | continuous process | uses a renewable raw material |
| B | uses a renewable raw material | continuous process |
| C | produces pure ethanol | uses yeast |
| D | high temperature and pressure | batch process |
Answer: B
How many structural isomers have the molecular formula C5H12?
Answer: C
Nylon and PET are condensation polymers. Poly(ethene) is an addition polymer.
1 Poly(ethene) is made from monomers that contain C=C double bonds.
2 Nylon is a polyester.
3 Addition polymerisation forms water as a second product.
Which statements are correct?
Answer: D
Ethanol can be made by fermentation or from ethene.
Describe the conditions for fermentation.
Give one advantage and one disadvantage of fermentation compared with hydration of ethene.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | yeast, 25–35 °C, no oxygen glucose solution with yeast B1 warm (about 25–35 °C) B1 absence of oxygen (anaerobic) B1 | 3 |
| (b) | renewable; slow / impure advantage: uses renewable resources / low temperature B1 disadvantage: slow / batch process / impure ethanol B1 | 2 |
Alkanes are used as fuels.
Write a balanced equation for the complete combustion of propane, C₃H₈.
State what is meant by a saturated hydrocarbon.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | C₃H₈ + 5O₂ → 3CO₂ + 4H₂O correct formulae B1 balanced B1 | 2 |
| (b) | only single C–C bonds contains only single carbon–carbon bonds B1 | 1 |
This question is about alcohols and carboxylic acids.
Ethanol can be made by the fermentation of glucose.
Write the equation for the fermentation of glucose, C₆H₁₂O₆.
State two conditions needed for fermentation.
Calculate the maximum mass of ethanol made from 45 g of glucose. [Mᵣ: glucose, 180; ethanol, 46]
Explain why fermentation stops when the ethanol concentration reaches about 15%.
Ethanol is oxidised to ethanoic acid by acidified potassium manganate(VII). State the colour change and the type of reaction.
Ethanoic acid reacts with propan-1-ol in the presence of an acid catalyst. Name the ester formed and give its structural formula.
Ethanoic acid reacts with sodium carbonate. Write the equation and describe what is seen.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a)(i) | C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ C₂H₅OH and CO₂ as products B1 balanced B1 | 2 |
| (ii) | yeast; about 30 °C; absence of oxygen Any 2 of: yeast; 25–35 °C; absence of oxygen / anaerobic; aqueous solution B2 | 2 |
| (iii) | 23.0 g moles glucose = 0.250, moles ethanol = 0.500 M1 23.0 g A1 | 2 |
| (iv) | yeast is killed by the ethanol the ethanol kills / denatures the yeast (enzymes) B1 | 1 |
| (b) | purple to colourless; oxidation purple to colourless B1 oxidation B1 | 2 |
| (c) | propyl ethanoate, CH₃COOC₃H₇ propyl ethanoate B1 CH₃COOC₃H₇ B1 | 2 |
| (d) | 2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂; fizzing correct products CH₃COONa, H₂O, CO₂ B1 balanced B1 effervescence / fizzing / solid dissolves B1 | 3 |
Ethanol is used as a fuel and a solvent.
Write a balanced equation for the complete combustion of ethanol.
Give one use of ethanol other than as a fuel.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O correct formulae B1 balanced B1 | 2 |
| (b) | solvent; drinks; disinfectant solvent / in alcoholic drinks / antiseptic B1 | 1 |
Organic compounds are named according to their functional groups.
Name the functional group in carboxylic acids and in alcohols.
Give the name of CH₃CH₂CH₂OH.
Give the molecular formula of butene.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | –COOH; –OH carboxylic acid: –COOH B1 alcohol: –OH B1 | 2 |
| (b) | propan-1-ol propan-1-ol (propanol) B1 | 1 |
| (c) | C₄H₈ C₄H₈ B1 | 1 |
Ethanol, C₂H₅OH, and ethene, C₂H₄, are organic compounds.
Name the homologous series to which each belongs.
State two characteristics of a homologous series.
Draw the displayed formula of ethanol.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | alcohols; alkenes ethanol: alcohols B1 ethene: alkenes B1 | 2 |
| (b) | same general formula; same functional group; similar chemical properties; trend in physical properties Any 2 of: same general formula; same functional group; similar chemical properties; gradual change in physical properties B2 | 2 |
| (c) | H–C(H)(H)–C(H)(H)–O–H correct displayed formula showing all atoms and bonds B1 | 1 |
Ethene can be made by cracking long-chain alkanes.
Describe the conditions used for cracking.
Explain why cracking is important to the petrochemical industry.
Describe a test to distinguish ethene from ethane.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | high temperature; catalyst high temperature B1 catalyst (e.g. silica/alumina) or steam B1 | 2 |
| (b) | supply of short-chain fuels and alkenes there is more demand for short-chain alkanes (petrol) than supply B1 it also produces alkenes for making polymers B1 | 2 |
| (c) | bromine water decolourises with ethene add bromine water B1 ethene decolourises it (orange to colourless), ethane does not B1 | 2 |
In the 0620 syllabus, Organic Chemistry covers Formulae, functional groups & naming, Alkanes & alkenes, Alcohols & carboxylic acids, Polymers.
This page has 10 Organic Chemistry questions with answers. For more, the free generator on mentorriyaz.in builds a new Organic Chemistry paper with a full mark scheme each time you click.
Riyaz Shaikh has mentored IGCSE, IB and A Level students for 15+ years, one-on-one, online and in Mumbai. The hardest questions on this site are the ones he uses to find a student's weak points.
Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in