Alcohols Flashcards
What functional group do alcohols contain
Oh
What is methanol used for
Starting product in many industrial syntheses. Can be converted to polymers, paints, solvents, insulation , adhesives
What can ethanol be used for
Alcoholic drinks, fuel , solvent
How do the physical properties of alcohols differ to alkanes
Alcohols are:
Less volatile
Higher melting points
Greater water solubility
The differences in physical properties between alcohols and alkanes become much ? As the length of the chain increase
Smaller
Why are there physical differences between alcohols and alkanes
The alkanes have non-polar bonds because the electronegativity of hydrogen and carbon are similar
Therefore alkanes are very non-polar
The intermolecular forces between non-polar molecules are very weak London forces
Alcohols have a polar O-H bond because of the difference in electronegativity of the oxygen and hydrogen atoms
Alcohol moles are therefore very polar
The intermolecular forces will be very weak London forces but there will also be much stronger hydrogen bonds between the polar O-H groups.
Why is the volatility and boiling points different in alcohols than alkanes
In liquid state hydrogen bonds hold alcohol molecules together. These bonds must be broken in other to change the liquid alcohol into a gas. This requires more energy than overcoming the weaker London forces in alkanes so alcohols have a lower volatility than alkanes
Are alcohols soluble in water and why
Yes hydrogen bonds form between the polar -OH group of the alcohol and the water molecules
What does alcohol completely combust to
Carbon dioxide and water
What oxidises alcohols
Acidified potassium dichromate
What forms when alcohols are reacted with acidified potassium dichromate
Aldehyde
What happens as soon as the aldehyde is formed
It is distilled out to prevent it turning to a carboxylic acid
What do you have to do to make a carboxylic acid from alcohol
Heat under reflux
What are secondary alcohols oxidised to
Ketones
What is needed to turn secondary alcohols into alcohols
Hur
Oxidising agent
