Esters
Cambridge A-Level Chemistry (9701) · Unit 33: Carboxylic acids and derivatives (A Level) · 7 flashcards
Esters is topic 33.2 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 33 — Carboxylic acids and derivatives (A Level) , alongside Carboxylic acids and Acyl chlorides. In one line: Esters are produced via a nucleophilic acyl substitution reaction. The alcohol acts as a nucleophile, attacking the carbonyl carbon of the acyl chloride, resulting in the displacement of chloride ion and formation of the ester.
Marked as A2 Level: examined at A Level in Paper 4 (A Level Structured Questions) and Paper 5 (Planning, Analysis and Evaluation). It is not tested on the AS-only papers (Papers 1, 2 and 3).
The deck below contains 7 flashcards — 1 definition, 5 key concepts and 1 calculation — covering the precise wording mark schemes reward. Use the definition card to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
What type of reaction is used to produce esters from alcohols and acyl chlorides
Esters are produced via a nucleophilic acyl substitution reaction. The alcohol acts as a nucleophile, attacking the carbonyl carbon of the acyl chloride, resulting in the displacement of chloride ion and formation of the ester.
What the Cambridge 9701 syllabus says
Official 2025-2027 spec · A2 LevelThese are the exact learning outcomes Cambridge sets for this topic. The candidate is expected to be able to do each of these on the relevant paper.
- recall the reaction by which esters can be produced: (a) reaction of alcohols with acyl chlorides using the formation of ethyl ethanoate and phenyl benzoate as examples
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in Esters
- › Check the question conditions carefully; use 22.4 dm³ per mole for calculations involving gas at s.t.p.
What type of reaction is used to produce esters from alcohols and acyl chlorides?
Esters are produced via a nucleophilic acyl substitution reaction. The alcohol acts as a nucleophile, attacking the carbonyl carbon of the acyl chloride, resulting in the displacement of chloride ion and formation of the ester.
Write the general equation for the formation of an ester from an alcohol and an acyl chloride.
R'OH + RCOCl → RCOOR' + HCl, where R'OH is the alcohol, RCOCl is the acyl chloride, and RCOOR' is the ester.
Give the reagents required for the synthesis of ethyl ethanoate.
To synthesize ethyl ethanoate, you would need ethanol (CH₃CH₂OH) and ethanoyl chloride (CH₃COCl).
Draw the mechanism for the reaction of ethanol with ethanoyl chloride to produce ethyl ethanoate.
Ethanol attacks the carbonyl carbon of ethanoyl chloride. The C=O bond breaks, forming a tetrahedral intermediate. Chloride ion leaves, the C=O reforms, and a proton is lost, yielding ethyl ethanoate and HCl.
What are the products formed in the reaction between phenol and benzoyl chloride?
The reaction between phenol (C₆H₅OH) and benzoyl chloride (C₆H₅COCl) yields phenyl benzoate (C₆H₅COOC₆H₅) and hydrochloric acid (HCl).
Outline the steps in the mechanism for the formation of phenyl benzoate from phenol and benzoyl chloride.
Phenol attacks the carbonyl carbon of benzoyl chloride. Chloride ion is eliminated, and a proton is removed from the intermediate, resulting in the formation of phenyl benzoate and HCl.
Why is the reaction between an alcohol and an acyl chloride a more effective method for ester formation compared to reacting the alcohol with a carboxylic acid directly?
Acyl chlorides are more reactive than carboxylic acids due to the electron-withdrawing chlorine atom making the carbonyl carbon more electrophilic. This leads to a faster and higher-yielding reaction at lower temperatures.
More Chemistry flashcards
Browse every 9701 flashcard topic by syllabus area.
All Chemistry FlashcardsMore topics in Unit 33 — Carboxylic acids and derivatives (A Level)
Esters sits alongside these A-Level Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Esters deck
Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.
How to study this Esters deck
Start in Study Mode, attempt each card before flipping, then rate Hard, Okay or Easy. Cards you rate Hard come back within a day; cards you rate Easy push out to weeks. Your progress is saved in your browser, so come back daily for 5–10 minute reviews until every card reads Mastered.
Study Mode
Rate each card Hard, Okay, or Easy after flipping.