Alcohols Flashcards
what is the general formula for an alcohol?
CnH2n+1OH
How do we know if a an alcohol is primary, secondary or tertiary?
It depends on which carbon atom the OH group is bonded to.
Describe how ethanol could be converted into bromoethane.
Substitution reaction
• react with halide ion (NaBr) and concentrated sulfric acid
How do the volatilities of alcohols compare with the volatilities of similarly sized alkanes?
- Alcohols can hydrogen bond with each other
- Hydrogen bonding is the strongest type of intermolecular force and so alcohols have higher boiling points than other similarly sized alkanes
- Therefore alcohols are less volatile
What products are made when 2-methylpropan-2-ol is mixed with sodium bromide and concentrated sulfric acid?
make a haloalkane
• 2-bromo-2-methylpropane
Can alcohols dissolve in water and why?
Yes but this only applies to shorter chain molecules
• alcohol react with water via a hydrogen bond. This is because the positive charge on the hydrogen is attracted to the lone pair of electrons on the water.
Alkenes can be made from the __________
Dehydration of Alcohols
A dehydration reaction involves the use of _________
- An acid catalyst
* either concentrated sulphuric or phosphoric acid
Haloalkanes are made from __________
Alcohols via a substitution reaction.
A haloalkane is made when an alcohol is reacted with _________
- A halide ion source (e.g. NaBr)
* an acid catalysts (H2SO4)
Dehydration of non primary alcohols can lead to _________
3 different Alkenes
When alcohols are burned what is produced?
they react with oxygen in the air and make CO2 and H2O
Alcohols can be oxidised by using a ________ like _______
- mild oxidising agent
* potassium dichromate
Alcohols can be oxidised to ______, ________ and _______
1) aldehydes
2) keytones
3) carboxylic acids
How are alcohols oxidised?
using acidified potassium dichromate
what colour will the acidified potassium dichromate turn when reduced?
It will go from orange (dichromate ion) to green (chromate ion)
Can alcohols hydrogen bond with each other?
yes
Why are alcohols less votaile than molecules with similar relative mass?
Because alcohols have hydrogen bonding - strongest type of intermolecular force - therfore they have higher boiling points than molecules of a similar realative mass with no hydrogen bonding.
Why are alcohols combusted?
- they are used as fuels to generate energy
* when burn they reactvwith oxygen in the air to make CO2 and H2O. The alcohol is oxidised
