AQA A Level Chemistry
AQA A Level Chemistry 3.3.14 Organic Synthesis Exam Questions
Free AQA A Level Chemistry exam questions for 3.3.14 Organic Synthesis, with a mark scheme for every pack. Covers planning multi-step synthesis routes, reagents and conditions, converting functional groups and evaluating routes for hazards and efficiency.
3.3.14 Organic Synthesis exam questions
1 question pack of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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About AQA A Level Chemistry 3.3.14 Organic Synthesis
Organic synthesis brings together all of the AQA A Level organic chemistry. You need to plan routes of up to four steps between aliphatic and aromatic compounds, giving the reagent, conditions and type of reaction for each step, and the structure of each intermediate. You are also expected to consider how to make routes safer and greener, for example by using fewer steps, higher atom economy and less hazardous solvents. This topic relies on every reaction from 3.3.2 to 3.3.13, so a reaction map is the best revision tool. Examiners typically give a starting material and a target and award marks for each correct reagent, condition and intermediate.
What you need to know
- Reaction maps Know how to interconvert alkanes, alkenes, halogenoalkanes, alcohols, aldehydes, ketones, carboxylic acids, esters, acyl chlorides, amides, nitriles and amines, and the aromatic routes from benzene.
- Extending the chain Use KCN in aqueous ethanol to convert a halogenoalkane into a nitrile, adding one carbon. Reduce the nitrile with LiAlH4 or H2 and a nickel catalyst to get a primary amine. Use KCN then dilute acid on a carbonyl compound to make a hydroxynitrile.
- Oxidation and reduction steps Acidified K2Cr2O7: distil for an aldehyde, reflux for a carboxylic acid, and use it on a secondary alcohol for a ketone. NaBH4 reduces aldehydes and ketones back to alcohols.
- Aromatic routes Benzene with concentrated HNO3 and H2SO4 at about 50 °C gives nitrobenzene; tin and concentrated HCl reduce it to phenylamine. Friedel-Crafts acylation with an acyl chloride and AlCl3 gives an aromatic ketone.
- Writing a good answer For each step give the reagent, the conditions and the intermediate structure or name. State 'reflux', 'distil', 'in ethanol' or 'aqueous' rather than just 'heat'.
- Green chemistry Better routes have fewer steps, higher atom economy, use safer solvents and reagents, and produce less waste.
Common mistakes in 3.3.14 Organic Synthesis
- Giving reagents without conditions. Many marks need both, for example 'KOH in ethanol, heat' for elimination.
- Writing 'heat' when reflux or distillation is required. The choice affects which product forms.
- Forgetting to add a carbon when the target has one more carbon atom than the starting material. Look for a cyanide step.
- Using concentrated sulfuric acid where dilute acid is needed, or acidifying dichromate with hydrochloric acid.
- Skipping intermediates. Draw or name the product of every step so the examiner can follow the route.
Try three 3.3.14 Organic Synthesis exam-style questions
1. Suggest a two-step synthesis of propanone from propene. Give reagents and conditions for each step and name the intermediate. (5 marks)
Show the mark scheme answer
Step 1: steam with a phosphoric acid catalyst at high temperature and pressure (or concentrated H2SO4 then water); intermediate propan-2-ol; step 2: acidified potassium dichromate(VI); heat (reflux or warm); propanone formed.
2. Suggest a two-step synthesis of propylamine from bromoethane. (4 marks)
Show the mark scheme answer
Step 1: KCN in aqueous ethanol, reflux; gives propanenitrile; step 2: LiAlH4 (or H2 with a nickel catalyst); gives propylamine (propan-1-amine).
3. Give the reagents and conditions needed to convert benzene into phenylamine in two steps. (4 marks)
Show the mark scheme answer
Step 1: concentrated nitric acid and concentrated sulfuric acid; at about 50 °C to give nitrobenzene; step 2: tin and concentrated hydrochloric acid; followed by sodium hydroxide.
3.3.14 Organic Synthesis FAQs
What does AQA A Level Chemistry 3.3.14 Organic Synthesis cover?
It covers planning multi-step routes between organic compounds, with reagents, conditions and intermediates, and choosing routes that are safer and more efficient.
Which paper is 3.3.14 Organic Synthesis examined in?
It is examined in Paper 2, and Paper 3 can also test it.
What is the best way to revise organic synthesis?
Draw one large reaction map with every functional group and label each arrow with reagents, conditions and reaction type. Then practise routes from past questions without notes and check every condition.
