Alkaline hydrolysis of esters - me explaining it to you guys!

[balloonsandhighlighters]

Hi, ok so i just revising chem paper 3, and thought, hey, i should write what i just learnt on here! So here is the explanation of the alkaline hydrolysis of esters! Is this on the syllabus? I don't know lol but its in my chemistry book so worth learning

Esters can be hydrolysed to an alcohol and the sodium salt of the carboxylic acid (NOT the carboxylic acid)

How? Well, we use dilute sodium hydroxide (aq) and heat the mixture UNDER REFLUX.

So,

ester + sodium hydroxide --> alcohol + sodium carboxylate

Let me give you an example,

ethyl ethanoate + sodium hydroxide --> ethanol + sodium ethanoate

don't forget, we must heat it under reflux, as we do with all hydrolysises

Ok. Now, how do we get the carboxylic acid instead of sodium carboxylate? Easy! All you have to do is add HCl (aq) to the hydrolysis products and voila! The Carboxylic acid.


I hope I helped!

 

[areebaization]

what's reflux? and in methyl ethanoate which is the acid and which is the alcohol!
TY for the explanation though

 

[BumbleBEA]

what's reflux? and in methyl ethanoate which is the acid and which is the alcohol!
TY for the explanation though

Methyl= From Methanol

Ethanoate= From Ethanoic Acid

 

[fishcook]

you need to know this for the hydrolysis of fats -which is an ester
the sodium salts you get is used to make soaps.

 

[balloonsandhighlighters]

what's reflux? and in methyl ethanoate which is the acid and which is the alcohol!
TY for the explanation though

reflux is basically using the liebig condenser ( a type of condenser with water surrounding it to keep it cool) in the vertical position (usually a liebig condenser is used in the horizontal position). Heating under reflux means that you have a water bath under the liebig condenser, and in the condenser are the chemicals.


No problem!

 

[balloonsandhighlighters]

you need to know this for the hydrolysis of fats -which is an ester
the sodium salts you get is used to make soaps.

Oh yeh i'm so silly! aahaha i forgot that fats were esters!

 

[Nibz]

This is too much for IGCSE level. There is no point in learning extra things which are not in your syllabus.
I don't think the Acid-Base hydrolyis of Esters and the concept of heating under reflux are in IGCSE syllabus. This is all A-level Chemistry.

Just learn the Esterification of Alcohol and Carboxylic Acids, uses of esters and their structure formulae. That's all.

 

[fishcook]

nope, you need to know the hydrolysis of fat which makes soaps and its salt name. its in our syllabus.