OxfordAQA International A Level Chemistry
OxfordAQA International A Level Chemistry 3.3.14 Organic Synthesis Exam Questions
Free OxfordAQA International A Level Chemistry revision for 3.3.14 Organic Synthesis: what you need to know, common mistakes and exam-style questions with answers. Covers planning syntheses of up to four steps, reagents and conditions, atom economy and safer, greener processes.
Practise 3.3.14 Organic Synthesis with past papers
Once you have learnt this topic, find the 3.3.14 Organic Synthesis questions in real OxfordAQA International A Level Chemistry past papers and mark them with the mark scheme. Doing lots of real questions is the quickest way to learn how examiners ask about each idea.
StemUp mark scheme flashcards
A-Level Chemistry Flashcards for 2027 Onwards
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Then test yourself with the questions on this page.
From £10.99View flashcards
About OxfordAQA International A Level Chemistry 3.3.14 Organic Synthesis
Organic synthesis is an A2 topic examined in Unit 4 that brings together all the organic chemistry in the course. You need to plan syntheses of up to four steps, giving the reagent, conditions and intermediate for each step, using the reactions you have met in alkanes, halogenoalkanes, alkenes, alcohols, carbonyl compounds, carboxylic acids and derivatives, aromatic compounds and amines. You also need to explain why chemists aim to design processes that do not need a solvent, use non-hazardous starting materials, and have high atom economy. Examiners usually reward precise reagents and conditions, such as aqueous versus ethanolic, and penalise vague answers.
What you need to know
- Planning a route Work forwards from the starting material and backwards from the target, looking for a functional group that links them. Each step should have a named reagent, conditions and the intermediate formed.
- Key conversions Halogenoalkane to alcohol: warm aqueous NaOH. Alcohol to aldehyde: acidified potassium dichromate(VI), distil. Aldehyde to hydroxynitrile: KCN then dilute acid. Alkene to halogenoalkane: HBr. Alcohol to alkene: concentrated H2SO4 or H3PO4, heat.
- Adding a carbon Use KCN with a halogenoalkane, or KCN with an aldehyde or ketone, to increase the carbon chain length by one.
- Aromatic routes Benzene to nitrobenzene: concentrated nitric and sulfuric acids. Nitrobenzene to phenylamine: tin and concentrated HCl. Benzene to phenyl ketone: acyl chloride with AlCl3.
- Green chemistry Better processes avoid solvents where possible, use non-hazardous starting materials and have high atom economy, which reduces waste and cost.
Common mistakes in 3.3.14 Organic Synthesis
- Giving a reagent without conditions. For example, NaOH alone is not enough; state aqueous and warm, or ethanolic and hot.
- Using an oxidising agent to make an alcohol from an aldehyde. You need a reducing agent such as NaBH4.
- Forgetting to acidify after alkaline hydrolysis when the free acid is needed.
- Trying to oxidise a tertiary alcohol or a ketone to a carboxylic acid. These do not oxidise under normal conditions.
Try three 3.3.14 Organic Synthesis exam-style questions
1. Give a two-step synthesis of propanone from propene, including reagents and conditions. (4 marks)
Show the mark scheme answer
Concentrated sulfuric acid, then warm with water; intermediate is propan-2-ol (via the more stable secondary carbocation); acidified potassium dichromate(VI), heat; propanone formed.
2. Suggest a two-step synthesis to convert bromoethane into propanoic acid. (4 marks)
Show the mark scheme answer
KCN in ethanol, heat under reflux; gives propanenitrile; hydrolysis by heating with dilute acid (for example HCl); gives propanoic acid.
3. Explain why chemists prefer reactions with a high atom economy. (2 marks)
Show the mark scheme answer
Less waste is produced; fewer resources used / more sustainable / lower cost.
3.3.14 Organic Synthesis FAQs
What does OxfordAQA International A Level Chemistry 3.3.14 Organic Synthesis cover?
It covers planning syntheses of up to four steps, reagents and conditions, atom economy and safer, greener processes.
Which unit is 3.3.14 Organic Synthesis examined in?
It is examined in Unit 4, an International A2 paper covering organic and physical chemistry. The Unit 5 practical and synoptic paper can also assess it.
How do I revise organic synthesis?
Make a reaction map linking every functional group in the course, with the reagent and conditions on each arrow. Then practise two- and three-step routes, checking each step against your map.
