Chemguide: Support for CIE A level Chemistry
Learning outcome 18: Carboxylic acids and derivatives
18.1: Carboxylic acids
This statement is about the formation of carboxylic acids from primary alcohols, aldehydes, nitriles and esters.
Before you go on, you should find and read the statement in your copy of the syllabus.
Start by reading the page introducing carboxylic acids.
This covers the structures, names and physical properties, including an introduction to the salts such as sodium ethanoate.
Statement 18.1.1(a): The formation of carboxylic acids from primary alcohols or aldhehydes
You will find this in the first half of the page about making carboxylic acids. You will need some basic experimental details as well as the chemistry of the reactions.
CIE is happy for you to use the simple versions of the equations with oxygen in square brackets.
Statement 18.1.1(b): The formation of carboxylic acids from nitriles
(You might prefer to leave this until after you have looked at nitriles in Section 19.2. I will remind you at the time.)
You will find this in the second half of the same page about making carboxylic acids. Again, don't forget some experimental details.
This is a commonly asked question by CIE, following on from the formation of a nitrile either from the reaction between a halogenoalkane and cyanide ions, or the reaction between a carbonyl compound and HCN. You can't afford not to know this!
CIE normally ask about acid hydrolysis, and seem to prefer hydrolysing it with dilute sulfuric acid rather than hydrochloric acid. It really doesn't matter. If you use the ionic equation, it just shows hydrogen ions anyway.
The alkaline hydrolysis wasn't specifically mentioned in syllabuses before 2022, but it is now mentioned in two places (here and under nitrile chemistry). The fact that you may not easily find questions about it in pre-2022 papers doesn't mean that it isn't likely to come up now.
Statement 18.1.1(c): The formation of carboxylic acids from esters
(You might prefer to leave this until after you have looked at nitriles in Section 18.2. I will remind you at the time.)
You will find this on the page about hydrolysing esters. Ignore the last part of the page about making soap.
© Jim Clark 2020