Module 4 - Alcohols

Question 1

What is the functional group of an alcohol?

Answer 1

Hydroxyl group -OH

Question 2

What is the genmeral formula for an alcohol?

Answer 2

CnH2n+1OH

Question 3

How do you name alcohols?

Answer 3

-ol

Question 4

What kind of intermolecular forces do alcohols have? Why?

Answer 4

Hydrogen bonding, due to the
electronegativity difference in the OH
bond

Question 5

How do alcohols’ melting point
and boiling point compare to
other hydrocarbons’ of similar C
chain lengths? Why?

Answer 5

Higher, because they have hydrogen
bonding (strongest type of intermolecular
force) → stronger than London forces

Question 6

Are alcohols soluble in water?
Why does solubility depend on
chain length?

Answer 6

Soluble when short chain - OH hydrogen bonds
to hydrogen bond in water
Insoluble when long chain - non-polarity of C-H
bond takes precedence

Question 7

What makes an alcohol
primary?

Answer 7

C bonded to OH is only bonded to one
other C atom

Question 8

What makes an alcohol
secondary?

Answer 8

C bonded to OH is bonded to two other
C atoms

Question 9

What makes an alcohol
tertiary?

Answer 9

C bonded to OH is bonded to three other
C atoms

Question 10

Write an equation for the
combustion of ethanol

Answer 10

C2H5OH (l) + 3O2
(g) → 2CO2 (g) + 3H2O (l)

Question 11

What forms if you partially
oxidise a primary alcohol? (draw)

Answer 11

An aldehyde

Question 12

What conditions are needed to
partially oxidise a primary
alcohol?

Answer 12

Dilute sulphuric acid, potassium
dichromate (VI), distill product as it’s
produced, gentle heating

Question 13

Write an equation for the
partial oxidation of ethanol

Answer 13

CH3CH2OH (l) + [O] → CH3CHO (g) + H2O (l)

Question 14

What forms if you fully oxidise
a primary alcohol?

Answer 14

A carboxylic acid
(COOH)
One double bond oxygen

Question 15

What conditions are needed to
fully oxidise a primary alcohol?

Answer 15

Concentrated sulphuric acid, potassium
dichromate (VI), reflux, strong heating

Question 16

Write an equation for the full
oxidation of ethanol

Answer 16

CH3CH2OH (l) + 2[O] → CH3COOH (g) + H2O (l)

Question 17

What forms if you oxidise a
secondary alcohol?

Answer 17

A ketone

Question 18

What conditions are needed
for the oxidation of a
secondary alcohol?

Answer 18

Concentrated sulphuric acid, potassium
dichromate (VI), strong heating

Question 19

Write an equation for the
oxidation of propan-2-ol

Answer 19

CH3CH(OH)CH3
(l) + [O] → CH3COCH3
(g) + H2O (l)

Question 20

Is it possible to oxidise tertiary
alcohol?

Answer 20

No

Question 21

What is a dehydration
reaction?

Answer 21

A reaction where water is lost to form an
organic compound

Question 22

What are the products of
dehydration reaction of
alcohol?

Answer 22

Alkene and water

Question 23

What are the conditions
required for dehydration of
alcohol?

Answer 23

Concentrated sulfuric acid or
concentrated phosphoric acid and 170°C

Question 24

What are the products of the
halide substitution reaction
with alcohol?

Answer 24

Haloalkane and water

Question 25

In what form is the halide used
in halide substitution reaction?

Answer 25

In the form of hydrogen halide, e.g HBr

Question 26

How is hydrogen halide made
in situ? Give examples

Answer 26

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