Oxidation of Alcohols

Question 1

Primary alcohols can be oxidised to form…………which can undergo further oxidation to form

Answer 1

Primary alcohols can be oxidised to form aldehydes which can undergo further oxidation to form carboxylic acids

Question 2

Secondary alcohols can be oxidised to form ,,,,,,,,,,,only

Answer 2

ketones

Question 3

The oxidising agents of alcohols include

Answer 3

acidified K2Cr2O7 or acidified KMnO4

Question 4

Acidified means that the potassium dichromate(VI) is in a solution of

Answer 4

dilute acid (such as dilute sulfuric acid)

Question 5

For potassium dichromate(VI) to act as an oxidising agent, it itself needs to be reduced
This reduction requires

Answer 5

hydrogen (H+) ions which are provided by the acidic medium
When alcohols are oxidised the orange dichromate ions (Cr2O72-) are reduced to green Cr3+ ions

Question 6

Acidified potassium manganate(VII), KMnO4, is a ……………oxidising agent

Answer 6

purple

Question 7

As with acidified K2Cr2O7 the potassium manganate(VII) is in an acidic medium to allow reduction of potassium manganate(VII) to take place
When alcohols are oxidised, the purple manganate ions (MnO4-) are reduced to

Answer 7

colourless Mn2+ ions

Question 8

The primary alcohol is added to the oxidising agent and warmed
The aldehyde product has a lower boiling point than the alcohol reactant so it can be

Answer 8

distilled off as soon as it forms

Question 9

If the aldehyde is not distilled off how is carboxyli acid made

Answer 9

further refluxing with excess oxidising agent will oxidise it to a carboxylic acid

Question 10

Since ketones cannot be further oxidised, the ketone product does not need to be ,,,,,,,,,,,

Answer 10

distilled off straight away after it has been formed