Practice S3.2 Functional groups: Classification of organic compounds with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 2
A student is analyzing samples of different organic compounds in a school laboratory to identify their functional groups, which determine their chemical properties.
1.[1]
Define the term functional group in the context of organic chemistry.
2.[1]
Identify the functional group present in alcohols.
3.[2]
Name the functional group present in carboxylic acids and draw its displayed structure.
Question 2
HLPaper 2
The following infrared spectrum is for 2-butanone, an organic compound with the molecular formula .
1.[1]
Identify the functional group present in 2-butanone that corresponds to the strong absorption peak around 1715 .
2.[2]
Predict why there is no broad absorption peak in the region around 3200–3600 .
3.[2]
Discuss the significance of multiple sharp peaks appear between 1000-1300 in organic structure identification.
4.[3]
The IR spectrum of 2-butanone was recorded to monitor a chemical reaction.
Explain how this spectrum could be used to determine whether 2-butanol has been fully oxidized to 2-butanone.
5.[3]
2-butanone and butanoic acid have the same molecular formula.
Describe how their IR spectra would differ, and explain how these differences arise.
Question 3
SLPaper 2
The compound benzophenone contains two phenyl (benzene) rings bonded to a central carbonyl () group.
1.[1]
State the molecular formula of benzophenone.
2.[1]
Identify the functional group present in benzophenone.
3.[2]
Benzophenone is insoluble in water but soluble in organic solvents.
Explain this difference in terms of intermolecular forces.
Question 4
SLPaper 2
Urea is a small organic molecule excreted in the urine of mammals. It plays an important role in the removal of excess nitrogen from the body.
The structure of urea is shown below:
1.[1]
Identify the functional group present in urea.
2.[1]
Deduce the molecular formula of urea.
3.[2]
Write a balanced chemical equation for the formation of urea from ammonia and carbon dioxide.
4.[2]
Explain why urea is highly soluble in water. Refer to relevant intermolecular forces.
5.[1]
A student dissolves 6.00 g of urea in 100.0 g of water.
Calculate the amount of substance (in mol) of urea dissolved. (Molar mass = 60.06 )
6.[2]
Urea can form hydrogen bonds with water.
Draw a Lewis structure of urea and clearly indicate one possible hydrogen bond between urea and a water molecule.
Question 5
SLPaper 1A
Which compound can be oxidized when heated with an acidified solution of potassium dichromate(VI)?
Question 6
SLPaper 1A
Which type of reaction occurs when ethanol and butanoic acid react together in the presence of a catalyst?
Question 7
SLPaper 1A
Which type of reaction occurs between an alcohol and a carboxylic acid?
Question 8
HLPaper 1A
Which would be the most effective method to distinguish between liquid propan-1-ol and propan-2-ol?
Question 9
SLPaper 1A
Which molecule has a tertiary nitrogen?
Question 10
SLPaper 1A
Which of these reactions proceeds by a free radical mechanism in the presence of ultraviolet light?