O- Carboxylic acids & derivatives =)

Question 1

An alcohol reacts with ethanoyl chloride to form an
ester.
Describe what would be observed when the alcohol reacts with ethanoyl chloride. (1)

Answer 1

misty fumes (sweet-smelling)

Question 2

Suggest why aqueous ethanol is a suitable solvent when heating the coconut oil with KOH. (1)

Answer 2

dissolves both oil + KOH

Question 3

Give 2 industrial advantages, other than cost, of using ethanoic anhydride rather than ethanoyl chloride in the production of aspirin. (2)

Answer 3

1. ↓ vigorous reaction
2. ↓ dangerous- x produce toxic fumes (HCl)
3. ↓ corrosive (HCL< CH3COOH)
4. ↓ vulnerable to hydrolysis
5. ↓ volatile

Question 4

Which compound can be purified by forming a hot aqueous solution that recrystallises
on cooling?
[1 mark]
A Cyclohexene
B Ethanoic acid
C Phenylamine
D Benzoic acid

Answer 4

D

Question 5

CH3CH2COCl reacts with benzene in the presence of AlCl3 in an
electrophilic substitution reaction.
Give an equation for the reaction of CH3CH2COCl with AlCl3 to form the
electrophile. (1)

Answer 5

CH3CH2COCl + AlCl3 –> CH3CH2CO+ + AlCl4 -

Question 6

Benzoic acid can be prepared from ethyl benzoate. A mixture of ethyl benzoate and NaOH is heated under reflux for half an hour, to hydrolyse the ethyl benzoate.
State why reflux is used in this hydrolysis. (1)

Answer 6

Reflux ✔ reactant vapours to be returned to reaction mixture (none escapes)

Question 7

The percentage yield for the formation of benzoicacid from ethyl benzoate is 105%.
Explain why the yield is not 100%. (3)

Answer 7

impurities present in product/
product x dried