Alcohols Flashcards
What is the functional group of an alcohol?
-OH
What is the hydroxyl group responsible for?
Physical and Chemical properties
What is methanol used for?
High performance fuel
Chemical feedstock
What is ethanol used for?
Alcoholic drinks
Fuel
How do alcohols physical properties differ from the corresponding alkane?
Alcohols have a higher melting point, less volatile and have a greater solubility in water than the corresponding alkane
What intermolecular forces are present in an alcohol? Why?
Alcohols have London forces present
They also have a polar O-H bond
Hydrogen bonds between O-H group
Why do alcohols have a lower volatility than alkanes?
Presence of OH group and hydrogen bond
Requires more energy to overcome than weak London forces
Changes state less easily and so is less volatile
Why are alcohols soluble?
Can form hydrogen bonds with water
What happens to the difference in properties of alkanes and alcohols as chain becomes longer?
The influence of the -OH group becomes less and solubility of hydrocarbon reduces and becomes more similar to that of the alkane
What is a primary alcohol?
-OH group attached to a carbon atom that is attached to 2 hydrogen atoms and an alkyl group
What is an exception to the primary alcohol rule?
Methanol
What is a secondary alcohol?
-OH group is attached to a carbon atom that is attached to one hydrogen atom and two alkyl groups
What is a tertiary alcohol?
-OH group is attached to a carbon atom that is attached to no hydrogens and three alkyl groups
What is the usual oxidising mixture?
Potassium dichromate
Acidified with dilute sulfuric acid
What colour change occurs during oxidation?
Orange- Green
What alcohol can form carboxylic acids?
Primary alcohol under reflux
How are aldehydes formed?
Heating of a primary alcohol under distillation conditions to remove aldehyde as it is produced
How is a carboxylic acid formed?
Primary alcohol heated strongly under reflux with an excess of potassium dichromate
What are secondary alcohols oxidised to?
Ketones
Under Reflux
What are the conditions for a dehydration reaction of an alcohol?
Reflux Acid Catalyst (phosphoric acid catalyst or sulfuric acid conc.)
What type of reaction is dehydration?
Elimination
What are the conditions for making a haloalkane from an alcohol?
Reflux
Sulfuric Acid
Sodium Halide
