Alcohols Unit 4 Flashcards
Define an alcohol
Compounds in which one or more hydrogen atoms in an alkene have been replaced by a hydroxyl Group
Why does the boiling point of alcohols increase with increasing chain length
The attractions get stronger as the molecules get longer and have more electrons- increase size of temporary dipoles
What is complete oxidation called
Combustion
C2H5OH + O2 –> CO2 + H2O
How to oxidise alcohols
Add acidified potassium dichromate
What colour changes happens when you oxidise Butan-1-ol
Orange to green
Balanced equation for the oxidation of Butan-1-ol to a carboxylic acid
C4H9OH + 2[O] —> C3H7COOH + H2O
What conditions are need for the dehydration of an alcohol?
An acid catalyst phosphoric or sulphuric acid
And heat
What does the dehydration of an alcohol form
An alkene and a molecule of water
Which alcohol reacts the fastest with concentrated hcl
Tertiary
What are primary alcohols oxidised to and what does it require?
Aldehydes
Distillation
What happens to an aldehyde if heated further with excess acidified potassium dichromate and under reflux?
Carboxylic acid
What are secondary alcohols oxidised to and what does it require?
Ketones
Reflux
Colour changed of the three types of alcohols
Primary- green
Secondary- green
Tertiary- orange (no change)
Why can’t tertiary alcohols be oxidised
They don’t have a hydrogen atom attached to that carbon
Physical properties of haloalkanes
Immiscible with water
Boiling point depends on size and number of halogens
Define a nucleophile
An electron pair donor