4.2.1: Alcohols Flashcards
What is the functional group of an alcohol?
Hydroxyl group -OH
What is the general formula of an alcohol?
Cn H2n+1 OH
How do you name alcohols (one prefix, one suffix)?
Hydroxyl- OR -ol
What kind of intermolecular forces do alcohols have? Why?
Hydrogen bonding, due to the electronegativity difference in the OH bond
How do alcohols’ melting point and boiling point compare to other hydrocarbons’ of similar C chain lengths? Why?
Higher, because they have hydrogen bonding (strongest type of intermolecular force) → stronger than London forces
Are alcohols soluble in water? Why does solubility depend on chain length?
Soluble when short chain - OH hydrogen bonds
to hydrogen bond in water
Insoluble when long chain - non-polarity of C-H
bond takes precedence
What makes an alcohol primary?
OH group is attached to C with 2 H atoms and 1 alkyl group
What makes an alcohol secondary?
OH bonded to C atom with 1 H atom and 2 alkyl groups
What makes an alcohol tertiary?
C bonded to OH is bonded to three other C atoms
Write an equation for the combustion of ethanol
C2H5OH (l) + 3O2 (g) → 2CO2 (g) + 3H2O (l)
What forms if you partially oxidise a primary alcohol?
An aldehyde
What conditions are needed to partially oxidise a primary alcohol?
Dilute sulphuric acid, potassium dichromate (VI), distill product as it’s produced, gentle heating
Write an equation for the partial oxidation of ethanol
CH3CH2OH (l) + [O] → CH3CHO (g) + H2O (l)
What forms if you fully oxidise a primary alcohol?
A carboxylic acid
What conditions are needed to fully oxidise a primary
alcohol?
Concentrated sulphuric acid, potassium dichromate (VI), reflux, strong heating