11 mark
The displayed formula of an organic compound is shown below.
What is the systematic name of this organic compound?
Propyl propanoate
Propyl butanoate
Butyl propanoate
Butyl butanoate
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Carboxylic Acids & Esters (OCR A Level Chemistry)
Exam Questions
2 hours28 questions21 mark
Equal amounts of the four compounds are added to the same volume of water.
Which compound would produce the most acidic solution?
CH3CONH2
CH3COOH
CH3COOCH3
CH3COCl
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31 mark
Esters can be hydrolysed under acidic or alkaline conditions.
Which statement about the hydrolysis of esters is correct?
The alkaline hydrolysis of an ester is a reversible reaction
The acid hydrolysis of an ester uses sodium hydroxide under reflux
The alkaline hydrolysis of an ester produces the parent carboxylic acid and alcohol
The acid hydrolysis of an ester does not go to completion
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41 mark
Organic reactions can be completed by the use of acyl chlorides or acid anhydrides instead of carboxylic acids.
Which reason about the use of acyl chlorides and acid anhydrides is correct?
Acyl chlorides are safer and quicker to use than acid anhydrides
Acid anhydrides are less reactive than acyl chlorides
Acid anhydrides produce strong, corrosive acids as a byproduct of the reaction
Acyl chlorides are less expensive than acid anhydrides
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51 mark
Methanoic acid reacts with propanol in the presence of a small amount of concentrated sulphuric acid.
What is the correct name for the ester formed?
Methyl propyl sulfate
Methyl propanoate
Propyl ethanoate
Propyl methanoate
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11 mark
Which alcohol could be used to prepare HCOOCH(CH3)2?
Propan-1-ol
Propan-2-ol
2-Methylpropan-2-ol
Methanol
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21 mark
The structure of ester E is shown in the diagram below.
E is hydrolysed in the presence of hydrochloric acid.
Which are the products of this hydrolysis?
CH3CO2H and (CH3)2CHCH2CH2CHO
CH3CO2H and (CH3)2CHCH2CH2OH
CH3COCl and (CH3)2CHCH2CH2OH
CH3CHO and (CH3)2CHCH2CH2OH
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31 mark
Which of the following compounds could be used to produce ethyl propanoate?
|
(CH3CH2CO)2O |
CH3CH2CHO |
CH3CH2CH2OH |
|
|
A |
✓ |
✓ |
✓ |
|
B |
✓ |
✓ |
x |
|
C |
x |
✓ |
✓ |
|
D |
✓ |
x |
x |
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41 mark
The structure of the analgesic ibuprofen is shown below:
Which of the following is not a correct statement about ibuprofen?
It will react with alcohols to produce an ester
It will react with magnesium oxide to form a salt
It will react with sodium carbonate solution
It has geometric isomers
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51 mark
A student added equal amounts of four compounds to the same volume of water and measured the resulting pH.
Which compound would have produced the solution with the lowest pH?
CH3CH2CONH2
CH3CH2COOH
CH3CH2COOCH3
CH3CH2COCl
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11 mark
This question is about triesters with identical alkyl (R) groups. The triester is shown below.
- A triester has a relative molecular mass, Mr, of = 722 when each of the alkyl (R) groups has the formula CH3(CH2)12.
- When completely combusted, one mole of the triester with CH3(CH2)9 alkyl (R) groups reacts with 50 moles of oxygen.
- Triesters must be hydrolysed with dilute NaOH at a high temperature so the value of Kc is high.
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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21 mark
A student investigated the extent to which propyl butanoate was hydrolysed. The carboxylic acid extracted from 3.50 g of propyl butanoate reacted with 23.50 cm3 of 0.20 mol dm-3 sodium hydroxide.
What percentage of propyl butanoate was hydrolysed?
1.75 %
15.31 %
17.46 %
34.91 %
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31 mark
N-(4-hydroxyphenyl)ethanamide is commonly known as paracetamol.
Which statement(s) is/ are correct?
- Paracetamol has a relative molecular mass of 151.
- An addition-elimination reaction with ethanoic anhydride is preferred to the reaction with ethanoyl chloride because it is less exothermic.
- Recrystallisation would require a solvent in which paracetamol dissolves when cold but is insoluble when heated.
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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41 mark
Below is the structure of three molecules, X, Y and Z.
Which statement is correct?
The IUPAC name for molecule X is methylbutanoate.
On addition of NaHCO3, molecule X will effervesce.
In the dissociation reaction of Y, the value of Kc is close to 1.
Molecule Z has a chain isomer that is optically active.
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51 mark
Propanoyl chloride takes part in the following reactions:
- Reaction 1: Propanoyl chloride + methylamine
- Reaction 2: Propanoyl chloride + methanol
Which statement(s) is/are correct?
- Reaction 1 is a condensation reaction where the methylamine nitrogen lone pair attacks the ?+ carbonyl carbon to produce N-methylpropanamide.
- Reaction 2 is an addition-elimination reaction where the carbonyl oxygen lone pair causes a partial positive charge on the carbon atom, making it susceptible to nucleophilic attack.
- Propanoyl chloride is used in reactions 1 and 2 instead of propanoic anhydride because the reactions are quicker, safer and cheaper.
1, 2 and 3
Only 1 and 2
Only 2 and 3
Only 1
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