Module 4 - Alcohols Flashcards
What is the functional group of an alcohol?
Hydroxyl group -OH
What is the genmeral formula for an alcohol?
CnH2n+1OH
How do you name alcohols?
-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?
C bonded to OH is only bonded to one
other C atom
What makes an alcohol
secondary?
C bonded to OH is bonded to two other
C atoms
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? (draw)
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
(COOH)
One double bond oxygen
What conditions are needed to
fully oxidise a primary alcohol?
Concentrated sulphuric acid, potassium
dichromate (VI), reflux, strong heating
Write an equation for the full
oxidation of ethanol
CH3CH2OH (l) + 2[O] → CH3COOH (g) + H2O (l)
What forms if you oxidise a
secondary alcohol?
A ketone
What conditions are needed
for the oxidation of a
secondary alcohol?
Concentrated sulphuric acid, potassium
dichromate (VI), strong heating
Write an equation for the
oxidation of propan-2-ol
CH3CH(OH)CH3
(l) + [O] → CH3COCH3
(g) + H2O (l)
Is it possible to oxidise tertiary
alcohol?
No
What is a dehydration
reaction?
A reaction where water is lost to form an
organic compound
What are the products of
dehydration reaction of
alcohol?
Alkene and water
What are the conditions
required for dehydration of
alcohol?
Concentrated sulfuric acid or
concentrated phosphoric acid and 170°C
What are the products of the
halide substitution reaction
with alcohol?
Haloalkane and water
In what form is the halide used
in halide substitution reaction?
In the form of hydrogen halide, e.g HBr
How is hydrogen halide made
in situ? Give examples
A salt is reacted with acid to form the hydrogen halide
E.g sodium bromide reacts with sulfuric acid to form HBr
When iodine is reacted phosphoric acid is used as
sulfuric acid oxidises iodide ions into iodine
