Revision NotesExam QuestionsPast Papers
A LevelChemistryCIEExam Questions7. Organic Chemistry (A Level Only)7.5 Carboxylic Acids & Derivatives (A Level Only)

Carboxylic Acids & Derivatives (A Level Only) (CIE A Level Chemistry)

Exam Questions

2 hours11 questions
Easy
Medium
1a1 mark

This question is about derivatives of carboxylic acids.

Fig 1.1 shows the structure of a carboxylic acid derivative.

 

butanoyl-chloride

Fig 1.1

State the name of the carboxylic acid derivative in Fig 1.1.

How did you do?

1b2 marks

Ethanoyl chloride reacts with ethanol to form ethyl ethanoate as shown in Fig 1.2.

formation-of-ethyl-ethanoate-from-ethanoyl-chloride
Fig 1.2

i)
Name the other product formed in this reaction.
[1]
ii)
This reaction can be described as an esterification reaction or an acylation reaction.

   Explain why this reaction can also be described as a condensation reaction.

 [1]

How did you do?

1c1 mark

Ethanoyl chloride can also react with ammonia to form ethanamide. 

Write an equation for this reaction. 

How did you do?

1d1 mark

During the preparation of propanoyl chloride, SO2 and HCl were also produced. 

Name the two reactants used to form propanoyl chloride. 

How did you do?

Did this page help you?

2a1 mark

Benzoic acid can be formed from the oxidation of methylbenzene. 

Draw the displayed formula of benzoic acid.

How did you do?

2b5 marks
i)
State the reagents and conditions needed to oxidise methylbenzene to benzoic acid. 

[3]

ii)
Give two observations that could be made during this reaction.

[2]

How did you do?

2c1 mark

Write an equation to show that benzoic acid acts as a weak acid. 

How did you do?

Did this page help you?

3a1 mark

Propanoyl chloride is used for the synthesis of other organic compounds. 

Draw the skeletal formula for propanoyl chloride. 

How did you do?

3b3 marks
i)
Name the two products formed when propanoyl chloride undergoes hydrolysis.
[2]
ii)
Name the mechanism by which hydrolysis occurs. 
[1]

How did you do?

3c2 marks

Explain why propanoyl chloride will more readily undergo hydrolysis compared to 2-chloropropane.

How did you do?

Did this page help you?

1a2 marks

Acyl chlorides are commonly used carboxylic acid derivatives. 

Ethanoyl chloride reacts with an excess of ammonia. 

A student proposes the following equation to represent the reaction:

CH3COCl + NH3  →  CH3CONH2 + HCl

Correct and explain the student's error.

How did you do?

1b3 marks

N-methylethanamide can also be formed from ethanoyl chloride. 

i)
Draw the skeletal formula of N-methylethanamide.

[1]

ii)
Write an equation for the formation of N-methylethanamide from ethanoyl chloride. 

[2]

How did you do?

1c1 mark

Ethanoyl chloride will react with 2-methylpropan-1-ol to form an ester. 

Draw the structure of the ester formed.

How did you do?

Did this page help you?

2a1 mark

Esters can be formed from carboxylic acids and acyl chlorides.

Write an equation for the formation of the ester formed from methanol and propanoic acid.

How did you do?

2b2 marks

Propanoyl chloride can be prepared from propanoic acid. 

i)
Write an equation for the preparation of propanoyl chloride from propanoic acid and phosphorus(V) chloride. 

[1]

ii)
Give one observation of this reaction. 

[1]

How did you do?

2c5 marks

Name and outline a mechanism for the reaction between methanol and propanoyl chloride to form methyl propanoate.

How did you do?

2d2 marks

Describe two advantages of using propanoyl chloride over propanoic acid in the preparation of esters in industry.

How did you do?

Did this page help you?

3a3 marks

Benzoic acid can be formed from methylbenzene. 

This process occurs in two stages. 

methylbenzene       rightwards arrow with Step space 1 on top   potassium benzoate    rightwards arrow with Step space 2 on top  benzoic acid        

 

i)
Draw the displayed formula for methylbenzene.
[1]
ii)
Draw the displayed formula for benzoic acid.
[1]

How did you do?

3b3 marks
i)
Name the reaction that takes place in step 1.  
[1]
ii)
Describe the conditions and reagents needed for step 1 and 2 of this reaction.

Step 1: ..........................
Step 2: ..........................
[2]

How did you do?

3c2 marks

Describe the observations that could be made during step 1.

How did you do?

3d3 marks

Describe and explain the relative acidities of benzoic acid and phenol. 

How did you do?

Did this page help you?

4a3 marks

This question is about butanoyl chloride. 

Butanoyl chloride can be produced from butanoic acid. 

i)
Draw the displayed formula of butanoyl chloride. 
[1]
ii)
Give the name and formula of a reagent that produces butanoic acid from butanoyl chloride. 

[2]

How did you do?

4b3 marks
i)
Explain why butanoic acid is a weaker acid than 2-chlorobutanoic acid.

[2]

ii)
Draw the skeletal formula for 2-chlorobutanoic acid.

[1]

How did you do?

4c1 mark

Name a chloro-substituted butanoic acid that is a strong acid than 2-chlorobutanoic acid. 

How did you do?

4d4 marks

Butanoyl chloride can undergo hydrolysis. 

Outline a mechanism for the hydrolysis of butanoyl chloride. 

How did you do?

4e5 marks

Explain the relative ease of hydrolysis for butanoyl chloride, chlorobenzene and 1-chorobutane. 

How did you do?

Did this page help you?

5a2 marks

Methanoic acid, HCO2H, has a similar acid strength to propanoic acid.

Describe a chemical test to distinguish between these two acids. Name the acid which gives a positive result in this test and describe the observations that would be made.

How did you do?

5b3 marks

The ester phenyl propanoate, C2H5CO2C6H5, can be made from phenol and propanoic acid in a two step synthesis.

The first step produces an acyl chloride.

For this two step synthesis,

  • draw the structure of the product of the first step
  • state the reagents and conditions needed for each step of the synthesis

How did you do?

5c1 mark

Explain why an acyl chloride should be formed first for the reaction in part (b).

How did you do?

Did this page help you?