Syllabus Edition

First teaching 2023

First exams 2025

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Functional Groups: Classification of Organic Compounds (HL IB Chemistry)

Exam Questions

7 hours115 questions
1a1 mark

Define the term hydrocarbon.

1b2 marks

State the general formula for the following hydrocarbon families.

Alkanes …………………………

Alkenes …………………………

1c1 mark

State the IUPAC name of the following hydrocarbon.

10-1-ib-sl-sq-easy-q1c-pent-1-yne

1d3 marks

A student stated that as the number of carbon atoms increases in an alkane, the boiling point increases. State if the student is correct and justify your answer. 

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2a2 marks

Propanal and propanone have the same molecular formula, C3H6O, but have different structures. Draw the displayed structures of propanal and propanone. 

2b1 mark

State the type of isomerism that is exhibited by propanal and propanone.

2c1 mark

Butanone can be reduced to a secondary alcohol by LiAlH4. State the name of this alcohol. 

2d1 mark

State the general formula of an alcohol.

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3a3 marks

Name the three possible isomers of C5H12.

3b1 mark

Using IUPAC rules state the name of the molecule shown in the image below.

10-1-ib-sl-sq-easy-q3b-3d-but-2-ene

3c1 mark

Draw the sterochemical drawing of methane.

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4a2 marks

Three isomers of pentane are shown below.

1

Give the IUPAC names of isomers B and C.

4b3 marks
Predict the number of different hydrogen environments in each of the isomers from part (a).
4c2 marks

The displayed formula of propanal is shown.

WGbWjbT6_2

State the number of 1H NMR signals that would appear in the 1H NMR of propanal and state the ratio of the area under the peaks in which they would appear.

4d2 marks

Propanal and propanone, shown below, both have the same molecular formula C3H6O.

3

Explain how propanone gives a different  1H NMR spectrum compared to propanal.

4e1 mark
Using section 21 of the data booklet, state the chemical shift for the 1H NMR of propanone.

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5a2 marks

Using section 21 of the data booklet, state the chemical shift for hydrogens a and b  in the 1H NMR of propanal.

4

5b1 mark

The structure of the amino acid glycine is shown below.

5

State the number of peaks found in the 1H NMR spectrum of glycine.

5c1 mark

State the ratio of the areas under the hydrogen peaks for glycine.

5d1 mark

The chemical shift for the protons in the NH2 protons in glycine is 1.0 - 4.5 ppm.

Using section 21 of the data booklet, predict the other 1H NMR chemical shifts for glycine.

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6a1 mark

Under certain conditions, butan-1-ol can be oxidized to the compound with the infrared spectrum shown below.

ir-spectrum

Using section 20 of the data booklet, state the name of the compound that has produced the spectrum shown.

6b1 mark

State what the molecular (parent) ion, M+ peak, in the mass spectrum of a hydrocarbon containing 12C and 1H represents.

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7a2 marks

Geraniol is an organic molecule that contains alkene and alcohol functional groups.

The mass spectrum of geraniol is shown below.

mass-spectrum-geraniol

i)    State how this mass spectrum can be used to confirm the molar mass of geraniol.

[1]


ii)    Give the formula of an ion that could be responsible for the peak at m/ z = 69.

[1]

7b1 mark

A sample of propan-2-ol was heated under reflux with potassium dichromate(VI) acidified with sulfuric acid, and then the mixture was distilled. 

Apart from the peaks due to the C—C and C—H bonds, what peak(s) would be present in the infrared spectrum of the distillate.

7c2 marks

The compound shown below can be analysed to obtain infrared and mass spectra.

heptane

Using section 22 of the data booklet, suggest the molecular formulae of the ions responsible for peaks in the mass spectrum with the following m/z values.

i)        15

[1]

ii)       100

[1]

7d2 marks

The mass spectrum shown below was obtained for propanal, CH3CH2CHO.

UzoggQTO_mass-spectrum-q

i)    Use the mass spectrum to show that the empirical and the molecular formulae of the compound mentioned are the same.

[1]

ii)   Using section 22 of the data booklet, suggest the species responsible for the peak at m/z = 29.

[1]

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8a2 marks

This question is about some isomeric alcohols with the molecular formula C5H12O.

Some alcohols were heated with potassium dichromate(VI) and sulfuric acid. The organic compounds were separated from the reaction mixtures and purified.

The infrared spectra of two of these organic compounds are shown below.

compound-y-and-z

Using section 20 of the data booklet, deduce the type of compound responsible for each spectrum.

Include in your answer references to wavenumbers and their corresponding bonds.

8b2 marks

State what is meant by the term ‘fingerprint region’ on infrared spectra and explain how this can be used to identify primary, secondary and tertiary halogenoalkanes.

8c1 mark

 The infrared spectrum a student obtained of an organic molecule which contains carbon, hydrogen and oxygen atoms is shown below.

ir-spectrum-2

Use section 20 of the data booklet and information from the infrared spectrum to explain how the student deduced that the spectrum shows the presence of a carbonyl group.

8d2 marks

In an experiment to prepare a sample of ethanal, CH3CHO, ethanol, C2H5OH, is reacted with acidified potassium dichromate (VI) and the reaction mixture is distilled. The infrared spectra for ethanol and ethanal are shown below.

ethanol-ir-spectrum

ethanal-ir-spectrum

i)    State the bonds that give rise to the absorption in the ethanol spectrum at 3400 cm-1 and the absorption in the ethanal spectrum at 1720 cm-1.

[1]

ii)    Explain why the absorption at 3400 cm-1 in the ethanol spectrum does not appear in the spectrum for ethanal.

[1]

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9a1 mark

Define the term stereoisomers.

9b2 marks

State the conditions needed for a compound to show cis-trans isomerism.

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10a1 mark

The chemical and physical properties of optical isomers are identical. However, there are some other differences that can be used to distinguish isomers from each other.
In terms of properties, state one difference between optical isomers.

10b2 marks

Describe how you can detect optical activity in a sample.

10c1 mark

The structure of one optical isomer of a chlorofluorocarbon is shown below.

hydroflurocarbon-enantiomer

Draw the structure of the other enantiomer.

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11a1 mark

State what is meant by the term a chiral carbon.

11b2 marks

The skeletal structure of an organic compound is shown below.

ib-isomers-5

Identify the chiral carbons. 

11c1 mark

Explain why carbon a cannot be a chiral carbon.

ib-isomers-7a
11d2 marks

The figure below identifies a different carbon, b, in the organic compounds structure.

ib-isomers-8a

Complete the figure below to show the 3D representations of the optical isomers formed at carbon b

ib-isomers-8b

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12a1 mark

Define the term racemic mixture.

12b1 mark

Describe the composition of enantiomers when a reaction mixture is optically active.

12c1 mark

Carvone is an optically active molecule which is found widely in plants, mostly in caraway seeds and spearmint leaves. The structure is shown below.

carvone

Mark on the diagram using an asterisk (*) the chiral carbon which causes this structure to exhibit optical isomerism.

12d1 mark

Draw the structure of the other optical isomer formed by carvone shown in part (c).

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13a3 marks

Three important analytical techniques in the chemist's toolkit are Mass Spectrometry, MS, Infrared Spectroscopy, IR, and Nuclear Magnetic Resonance Spectroscopy, NMR.

For each technique identify the characteristic chemical information provided.

13b4 marks

For each of the following, identify their significance in an 1H NMR spectrum: number of peaks, area under each peak, chemical shift and splitting patterns.

13c2 marks

1H NMR spectroscopy uses tetramethylsilane. State its formula and purpose in 1H NMR spectroscopy.

13d3 marks

State three advantages of using TMS in an 1H NMR spectrum.

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14a1 mark

Part of the 1H NMR spectrum of an organic compound is shown below:

7-1

Determine the number of unique hydrogen environments

14b1 mark

Deduce the whole number ratio of the hydrogen environments in the spectrum.

14c4 marks

State the splitting patterns present in the spectrum and suggest what information could be obtained from the patterns.

14d2 marks

Assign peaks X, Y and Z to the correct location shown in the compound:

8-1

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15a2 marks

An organic molecule with molecular formula C2H4O is analysed using MS, IR and 1H NMR. Use sectionS 20, 21 & 22 of the Data booklet to help you answer this question.

The MS is shown below:

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q4a

Determine the relative molecular mass from the spectrum and account for the peak at m/z 29.

15b1 mark

The IR spectrum of the same compound is shown below.

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q4b

Identify the functional group responsible for the peak at X

15c3 marks

The 1NMR spectrum of C2H4O is shown below:

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q4c

Account for the peaks at 2.2 ppm and 9.8 ppm and their relative areas.

15d1 mark

Deduce the displayed structure of this compound from the spectroscopic information.

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16a2 marks

The MS of compound P is shown below. Compound P contains carbon, hydrogen and oxygen only. Use sections 20, 21 & 22 of the Data booklet to help you answer this question.

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q5a


Determine the relative formula mass of P and account for the peak at m/z 45.

16b2 marks

The IR spectrum of P is shown below. 

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q5b

Use the spectrum and your answer to part a) to deduce a functional group that could be present in P.

16c2 marks

The 1H NMR spectrum of P is shown below. 

ib-hl-sq-e-21-1-spectroscopic-identification-of-organic-compounds-q5c

Deduce what information can be found from the spectrum.

16d4 marks

A student suggests that P is propan-1-ol. Evaluate all the evidence from the spectra and determine whether the student is correct.

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1a3 marks

Organic compounds are classified into families called a homologous series.

State three features of members belonging to the same homologous series.

1b4 marks

Table 1 shows the boiling points of the first five members of the alkane family.

 Table 1

Alkane

Boiling point/ oC

methane

-162

ethane

-89

propane

-42

butane

-1

pentane

36

 

On the axes below in Figure 1, draw a graph of boiling point against the number of carbon atoms in the alkanes. Estimate the boiling point of the next member of the homologous series, hexane, C6H14, and show on your graph how you arrived at your estimated boiling point. 

Figure 1

10-1-ib-chemistry-sq-q1b-medium

Estimated boiling point of hexane : ________ oC

1c2 marks

State the general formula for an alkyne and give the molecular formula and name of the fifth member of the alkyne family.

1d2 marks

The boiling point of ethyne, C2H2, is -84 oC.

State with, with a reason, whether the boiling point of ethyne would be expected to be higher or lower than the boiling point of ethane, C2H6.

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2a3 marks

Geraniol is a colourless component of rose oil whose structure is shown in Figure 1.

 Figure 110-1-ib-chemistry-sq-q2a-medium

i)
State the names of the two functional groups found in geraniol.
[1]
ii)
Deduce the molecular formula of geraniol. 
[1]
iii)
Draw the displayed formula of geraniol. 
[1]
2b3 marks

Butan-2-ol is an organic compound used industrially to make butanone.

i)
Draw the displayed structure of butan-2-ol. 
[1]
ii)
Draw the displayed structures of a positional isomer and a functional group isomer of butan-2-ol.
[2]
2c2 marks

Draw and name all the branched-chain isomers of butan-2-ol.

2d1 mark

State, with a reason, the class of alcohols which butan-2-ol belongs to.

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3a2 marks

The formulae of four organic compounds are given in Table 1. Write the names of the compounds in the second column.

Table 1

compound

name

CH3CH2CH2CH(OH)CH3

 

CH3CH2COCH3

 

CH3CH2CH2OH

 

CH3CH2CH2CHO

 

3b2 marks

Which of the compounds in part (a) are structural isomers of each other and what type of isomerism do they show?

3c3 marks

Propofol is a drug used to reduce consciousness during medical procedures. The skeletal structure of propofol is given in Figure 1.

Figure 1

10-1-ib-chemistry-sq-q3c-medium

i)
Determine the empirical formula of propofol. 
[1]
ii)
Identify the number of positional isomers of propofol (not including propofol). 
[1]
iii)
State the names of two functional groups found in propofol.      
[1]
3d3 marks

Valeric acid, C5H10O2, is a straight chain carboxylic acid found in the plant Valeriana officinalis.

i)
State the general formula for a carboxylic acid.
[1]
ii)
Give the systematic name for valeric acid. 
[1]
iii)
Draw a condensed structural formula for valeric acid.
[1]

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4a5 marks

Draw and name all the possible isomers of C6H14.

4b2 marks

Figure 1 below shows a three-dimensional structure of a molecule.                                                  

Figure 110-1-ib-chemistry-sq-q4b-medium 

i)
Using IUPAC rules state the name of this molecule. 
[1]
ii)
Draw and name a functional group isomer of this molecule. 
[1]

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5a2 marks

Often, scientists will use analytical techniques such as infrared spectroscopy to determine if a desired reaction has taken place.    Outline how infrared spectroscopy generates useful information about an organic molecule.

5b2 marks

A chemist uses infrared spectroscopy to distinguish between two organic molecules, a primary alcohol, and an aldehyde. 

Use section 20 of the data booklet to state, with a reason, how the chemist could use the IR spectra produced to distinguish between these two molecules.

5c1 mark

The chemist fully oxidized the alcohol from part (b) and used IR spectroscopy to prove that the reaction had taken place. 

State how the chemist could use infrared spectroscopy to determine that the reaction had taken place. Use section 20 of the data booklet to support your answer.

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6a1 mark

Toluene is a common organic chemical with many industrial and commercial applications. Toluene is also known as methylbenzene. 

Draw the molecular structure of toluene.  

6b2 marks

State the number of 1H NMR signals that would be seen on the NMR spectrum of toluene and state the ratio of the area under the peaks in which they would appear.  

6c2 marks

Another derivative of benzene has the molecular formula C8H10. 

Draw the structures of the four possible isomers of this derivative.

6d7 marks

Infrared spectroscopy is a common analytical tool used in chemistry, to identify or distinguish between different organic compounds. These could be compounds such as toluene which contain a benzene ring, or any other organic compound. IR is often used alongside other analytical tools, such as mass spectrometry, to help identify the unknown. 

An organic molecule, J, has the following composition by mass.  

            62.1% carbon

            10.3% hydrogen 

            27.6% oxygen

In the mass spectrum of J, the molecular ion peak has a value of m/z = 116. 

i)
Use this information to determine the molecular formula of J
[5]
ii)
State how an IR spectrum could be used to prove that compound J is a carboxylic acid. 
[2]

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7a1 mark

The analytical instruments used for identification of organic compounds are constantly being improved.            

 Mass spectroscopy is one such analytical tool which provides key information used to identify an unknown compound. 

An unknown compound has the empirical formula C2H4O, and its mass spectrum has a molecular ion peak at m/z 84.

Deduce the molecular formula of the compound.  

7b1 mark

Figure 1 below shows the IR spectrum of the unknown compound in part (a). 

Identify the bonds which are causing peak X and peak Y on the spectrum, using section 20 of the data booklet.

Figure 1

11-1-sq-q4b-medium-ib-chemistry

7c2 marks

The unknown compound is a carboxylic acid. Deduce the two possible carboxylic acid structural isomers.  

7d4 marks

For each of the isomers drawn in part (c), state the number of signals which would be seen in an 1H NMR spectrum and the ratio of the areas under the peaks.

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8a3 marks

A group of students are asked to distinguish between four samples of different organic compounds.            

The four samples are as follows: 

  • A primary alcohol 
  • A tertiary alcohol 
  • An aldehyde 
  • A carboxylic acid

Describe how the group of students could distinguish between the two different alcohols.

8b3 marks

One of the students wanted to distinguish between three compounds using mass spectrometry alone. The three compounds are shown below in Figure 1 and the mass spectrum for one of the compounds is shown in Figure 2.

Figure 1

11-1-sq-q5b-fig-1-medium-ib-chemistry

Figure 2

11-1-sq-q5b-fig-2-medium-ib-chemistryExplain, using Figure 2,  why determining the exact mass using mass spectrometry alone would not help in distinguishing between the samples of X, Y and Z shown in Figure 1.

8c2 marks

The three compounds from Figure 1 in part (b) were analysed using IR spectroscopy. 
 The spectrum of one of the compounds is shown below:
 

Figure 3

11-1-sq-q5c-medium-ib-chemistry

Identify which of the three compounds X, Y or Z this spectrum belongs to. Justify your choice. 

8d2 marks

State, with a reason, how infrared spectroscopy would be used to distinguish between the compounds X and Y from Figure 1 in part (b).

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9a2 marks

A molecule of oleic acid is shown.q1a_20-3_ib_hl_medium_sq

Oleic acid is a fatty acid which occurs naturally in different animals and plants.

Oleic acid exhibits stereoisomerism. Explain the meaning of this term and identify why oleic acid has stereoisomers.

9b4 marks

Crotonic acid is another fatty acid which has a similar structure to oleic acid. The molecular formula of crotonic acid is C4H6O2

i)

State the empirical formula of crotonic acid.

[1]

ii)
Crotonic acid has a carboxylic acid functional group. Draw the displayed formula of the positional and branch-chain isomers of crotonic acid.
[2]
iii)
Identify which of the isomers you have drawn shows E / Z isomerism.
[1]

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10a4 marks

A chemist is analysing a collection of organic compounds. The structural formulae of these compounds are shown.ma2a_20-3_ib_hl_medium_sq

Give the IUPAC name for the compounds to complete the table.

10b5 marks

This question refers to the compounds in the table in part (a)

i)
Identify the compounds which have chain isomers and draw their isomers.
[3] 
ii)
State the empirical formula of compound 3. 
[1]
iii)
Does compound 4 exhibit stereoisomerism? Explain your answer.
[1]

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11a2 marks

2-methylbut-2-ene can be converted into 2-methylbutan-2-ol, a liquid that smells of camphor. 

State the reagents needed to convert 2-methylbut-2-ene into 2-methylbutan-2-ol.

11b2 marks

The reaction in part (a) produces a small amount of an isomeric co-product, X, which is optically active. 

i)
State the meaning of optical activity. 
[1]
ii)
Draw the structure of X.
[1]
11c1 mark

What does optical activity indicate about the structure of X?

11d3 marks

Explain how optical activity can be detected using a polarimeter

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12a1 mark

Dichloroethene exists as two stereoisomers. Draw the structures of these isomers. 

12b1 mark

Explain why dichloroethene has stereoisomers.

12c1 mark

Draw the structures of the stereoisomers of 1-bromo-1-chloroethane, C2H4BrCl, and show the relationship between them.

12d3 marks

Explain the differences in chemical and physical properties between the isomers of C2H4BrCl

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13a2 marks

Ethane-1,2-diol, C2H6O2, can be distinguished from ethanedioic acid,C2H2O4, by a number of analytic techniques including MS, IR and NMR 

The MS of these molecules is shown below. 

Which spectrum belongs to each molecule? Justify your answer.

 

Spectrum A

q1a_21-1_ib_hl_medium_sq

Spectrum Bq1a2_21-1_ib_hl_medium_sq

13b2 marks

The IR spectra of ethane-1,2-diol, C2H6O2, and ethanedioic acid dihydrate, C2H2O4.2H2O, are shown in spectrum C and D. Use Section 20 of the Data Booklet to answer this question.

Spectrum Cq1b_21-1_ib_hl_medium_sqSpectrum D

q1b2_21-1_ib_hl_medium_sq

Which spectrum belongs to each molecule? Justify your answer.

13c3 marks

The 1H NMR spectrum of ethane-1,2-diol is shown in spectrum E. Explain the significance of the spectrum.

Spectrum Eq1c_21-1_ib_hl_medium_sq

13d2 marks

Predict the number of 1H NMR signals and splitting pattern for ethanedioic acid. 

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14a3 marks

During the production of a 1H NMR spectrum, tetramethylsilane (TMS) is mixed with the sample. 

i)
Draw the structural formula of TMS. 
[1]
ii)
State two reasons why this chemical is suitable to be used as the standard reference compound.
[2]
14b1 mark

Predict the number of peaks in the 1H NMR spectrum of 1,3-dichlorobenzene.

14c2 marks

The structural formula of ethylbenzene is shown below in Figure 1

Figure 1q2c_21-1_ib_hl_medium_sq  

i)
Predict the number of peaks in the 1H NMR spectrum of ethylbenzene.
[1]
ii)
One of the hydrogen atoms in the structure of ethylbenzene shown above is labelled with an asterisk (*).
Use Section 21 from the Data Booklet to suggest a range of δ values for the peak due to this proton in the 1H NMR spectrum of ethylbenzene.
[1]
14d1 mark

Predict the splitting patterns of the signals due to the ethyl group found in the 1H NMR spectrum of ethylbenzene.

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15a5 marks

Methyl cinnamate, C10H10O2, is a white crystalline solid used in the perfume industry. A sample of methyl cinnamate was analysed by 1H NMR spectroscopy.

A simplified spectrum is shown below. q3a_21-1_ib_hl_medium_sq

i)
Name the compound responsible for the peak at a chemical shift of 0 ppm. State its purpose.
[2]
ii)
Identify the proton environment that causes the peak at a chemical shift of 3.8 ppm by circling it on the structure of methyl cinnamate shown. Justify your answer.
[3]

 q3a1_21-1_ib_hl_medium_sq

15b2 marks

This question is about the use of 1H NMR spectroscopy to distinguish between isomers of C6H12O2

Draw the two esters with formula C6H12O2 that each have only two peaks, both singlets, in their 1H NMR spectra. The relative peak areas are 3:1 for both esters.

15c5 marks

The high resolution 1H NMR spectrum of another isomer of C6H12O2 is shown below.


q3c_21-1_ib_hl_medium_sq

 

The integration values for the peaks in the 1H NMR spectrum of this isomer, are given below.

Chemical shift, δ/ppm

3.8

3.5

2.6

2.2

1.2

Integration value

0.6

0.6

0.6

0.9

0.9

Splitting pattern

triplet

quartet

triplet

singlet

triplet

 

i)
Deduce the simplest ratio of the relative numbers of protons in each environment in the isomer.

 [1]

ii)
Use Section 21 from the Data Booklet and the information given to deduce the part of the isomer that causes the signal at δ= 3.5 and the part of the structure at the isomer that causes the signal at δ=1.2. Explain why the splitting patterns of these peaks are produced.
 [4]
15d2 marks

Four isomers of C6H12O2 are shown below.

q3d_21-1_ib_hl_medium_sq

Which isomer matches the 1H NMR spectrum below? Justify your choice.q3d2_21-1_ib_hl_medium_sq

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16a4 marks

An isomer with the molecular formula C5H10O2 was analysed by infrared spectroscopy, to confirm it was a carboxylic acid.

i)
Give the wavenumbers of two characteristic absorptions for a carboxylic acid. Indicate the bond responsible for each absorption. Suggest why one of the absorptions is broad. 
[3]
ii)
The 1H NMR spectrum of this isomer contains only two peaks with the integration ratio 9:1. Using this information from the spectra, deduce the structure of the isomer.
[1]
16b5 marks

This question is about two aldehydes, 2-aminopropanal and 3-aminopropanal.

q5b_21-1_ib_hl_medium_sq

 

Explain how 1H NMR spectra can be used to distinguish between these two aldehydes. You need to reference the splitting patterns and integration pattern in your answer.

16c1 mark

Suggest how the two isomers in part b) could be distinguished using mass spectroscopy.

16d7 marks

A compound X has a molecular formula of C6H14O. The infrared spectrum and 1H NMR spectrum of compound X are shown below.  

q5d_21-1_ib_hl_medium_sqq5d1_21-1_ib_hl_medium_sq

Using Sections 20 and 21 from the Data Booklet, deduce the structure of compound X. Justify each of your deductions.

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1a4 marks

State the IUPAC names for the isomers of C5H12O that are primary alcohols.

1b2 marks

State the IUPAC name for the following primary alcohols.

i)
2-chloro-but-2-en-1-ol-displayed-formula
[1]
ii)
CH2(Br)CH(CH3)CH2OH
[1]

1c1 mark

Draw the displayed formula for a straight chain isomer of CH2(Br)CH(CH3)CH2OH.

1d1 mark

The empirical formula of the compound in part b) i). 

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2a1 mark

Phenacetin is a pain killer though the use of this was banned as it was found to cause harm to kidney function.

10-1-ib-sl-sq-hard-q4a-phenacetin

Deduce the molecular formula of phenacetin. 

2b3 marks

Identify the names of the three functional groups present in phenacetin.

2c1 mark

Aspirin is a common pain killer and has the following structure.

Aspirin
State the empirical formula of aspirin.

2d1 mark

Aspirin is formed from ethanoic anhydride and compound A. State the IUPAC name of compound A.

bb813396-0587-4b67-8460-b5498458cd12

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3a1 mark
Deduce the number of isomers of C6H14

3b2 marks
State the IUPAC name of two branched isomers of C6H14

3c1 mark
Draw the displayed formula of a possible isomer of C6H12 that does not contain a π bond. 
3d3 marks

State the IUPAC names of two branched isomers of C5H10 that contain a π bond. 

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4a2 marks

An alcohol can be prepared by hydrolysing the halogenoalkane C2H5CHBClCH3 with aqueous sodium hydroxide. The infrared spectrum for C2H5CHClCH3  is shown below with the C–Cl bond absorption labelled.

e3fe76b9-de02-4c9a-a403-ce95f64b0829

Using section 20 of the data booklet deduce how IR spectroscopy will change as a result of the above reaction.

4b1 mark

The mass spectrum of (CH3)2CHCH2OH is shown below.

10-2

Deduce which ion is responsible for the peak with the greatest relative intensity.

4c3 marks

Alcohol X has the following percentage composition by mass. Carbon = 68.2%, hydrogen = 13.6%, oxygen = 18.2%. The molecular ion peak in the mass spectrum for alcohol X occurs at m/z = 88.

i)
Use this information and section 6 of the data booklet to show that the molecular formula for alcohol X is C5H12O. Include your working.
[2]

ii)
When alcohol X is oxidised, a carboxylic acid can be formed. State what information this gives about alcohol X.
[1]
4d3 marks

The mass spectrum of alcohol X has a major peak at m/z = 45.

i)
Draw the structure of the species that could give this peak.
[1]

ii)
Alcohol X has a branched chain. Deduce the structural formula and IUPAC name of alcohol X. Justify your answer.
[2]

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5a2 marks

Clenbuterol, shown below, is considered a performance enhancing drug and is believed to increase short term work rate and cardiovascular output.

11-1-ib-sl-sq-hard-q3a-clenbuterol

Deduce the functional groups marked x and y and state to which class they belong to.

5b2 marks

Determine the m/z value of the molecular ion, M+, of clenbuterol. Justify your answer.

5c
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5 marks

Two students, P and Q, were provided with the mass spectrum of an alkane, shown in below. Student P analysed peaks a and b and concluded that the alkane was one of two structures. Student Q analysed peaks a, b and c and was able to identify one possible alkane structure.

11-1-ib-sl-sq-hard-q3c

i)
Deduce which fragments of the alkane correspond to peaks a, b and c
[3] 
ii)
Suggest why the two students obtained different conclusions.
[2]

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6a4 marks

Four samples containing isomeric alcohols with molecular formula C4H10O, were studied using 1H NMR spectroscopy

Draw structural formulas of the alcohols and deduce the number of peaks in the NMR spectrum of each alcohol

6b2 marks

Two of the alcohols produce the same number of peaks in an 1H NMR spectrum. Suggest how they may be distinguished, by further spectroscopy analysis.

6c2 marks

Compound A can be converted into compound B via an intermediate species.

11-1-q4

Suggest how you would be able to determine the difference between Compounds A and B by analysis of their 1H NMR spectra.

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7a2 marks

Malonic acid, C3H4O4, is naturally occurring and found in many fruits and vegetables. It contains only carbon, hydrogen and oxygen.

The MS of malonic acid is show below.

ib-hl-21-1-q1a

Determine the relative molecular mass of malonic acid from the spectrum and account for the peak at m/z 45, using section 22 of the Data booklet to support your answer.

7b3 marks

The 1H NMR spectrum of malonic acid is shown below. Use section 21 of the Data booklet to help you with this question.

ib-hl-21-1-q1b

Suggest the identity of the proton environments seen in the spectrum and comment on the type of signals shown.

7c3 marks

The IR spectrum of malonic acid is shown below:

ib-hl-21-1-q1c
i)
Identify two characteristic peaks and bonds that can be found in the spectrum of malonic acid.
[2]
ii)
Explain how the spectrum can be used to distinguish malonic acid from ethanoic acid.
[1]
7d1 mark

Draw a displayed structure for malonic acid.

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8a4 marks

An organic compound, Q, of molecular formula CxHyOz, has the following MS. Use section 22 of the Data booklet to help you answer this question.

ib-hl-21-1-q2a
i)
Determine the relative molecular mass of Q and account for the peaks at m/z 15 and m/z 29.
[2]
ii)
Comment on the size of the peak at m/z 43.
[1]
iii)
Write an equation for the formation of the fragment at m/z 29.
[1]
8b1 mark

The IR spectrum of Q is shown below. 

ib-hl-21-1-q2b

Suggest which functional group(s) could be present in Q.

8c5 marks

The 1H NMR spectrum of Q is shown below.

10EqPbEg_ib-hl-21-1-q2c

Explain the relative peak heights and splitting patterns.

8d3 marks

Suggest the identity of Q, giving your reasons.

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9a2 marks

Compound A, has molecular formula C5H10 and occurs as 6 isomers. The table below shows the number of signals in the NMR spectrum of each isomer.

Isomer Number of 1H NMR signals
A 1
B 5
C 5
D 5
E 5
F 4

Suggest a structure for A and F.

9b3 marks

The IR spectrum of A is shown below.

21-1q3b

How does this spectrum distinguish A from the other isomers?

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10a1 mark

Oseltamivir is a drug used to treat and prevent influenza A and influenza B.

ap7K2wLr_21-1q4a

Predict the number of different proton environments in the molecule.

10b2 marks

Predict the chemical shift and the splitting pattern seen for the hydrogens on the carbon atom circled in the diagram. Use section 21 of the Data booklet.

10c3 marks

Predict three absorptions you would expect to see in the IR spectrum of oseltamivir. Use section 20 of the data booklet. 

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11a3 marks

Ibuprofen is an important painkilling drug. The structure is:

21-1q5a3

Part of the low resolution 1H NMR spectrum is shown below.

21-1q5a

The high resolution expansion of the peaks in B-F is:

8lvse2bn_21-1q5a2

The protons responsible for the peaks are numbered 1-7:

GXEnDSFZ_21-1q5a4

Complete the table to show the assignment of the missing peaks. 

Peak H atoms responsible
A 3 & 4
B  
C  
D  
E  
F  
Off spectrum x
11b2 marks

A sample of ibuprofen shows strong absorptions at 1716 cm-1 and 3345 cm-1 in an IR spectrum. Suggest the bonds responsible for these absorptions using section 20 of the data booklet. 

11c1 mark

A sample of ibuprofen rotates plane polarised light. Identify the feature in ibuprofen responsible for this.

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12a1 mark

Cholesterol, shown below, is a fatty chemical used by the body to build healthy cells.

cholesterol

State the number of chiral carbons in the cholesterol structure.

12b1 mark

A student suggested that cholesterol could be tested with plane polarised light to show that it contains chiral centres.

Is the student correct? Justify your answer.

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2 marks

Limonene, shown below, is a naturally occurring hydrocarbon with the molecular formula C10H16 and is commonly found in the rinds of citrus fruits such as grapefruit, lemon, lime and oranges.

limonene



Limonene exists as a pair of enantiomers; one enantiomer is responsible for a strong orange smell while the other is thought to smell like lemons.

Draw 3D representations of the two enantiomers of limonene.

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13a4 marks

Lactic acid has the molecular formula of C3H6O3, and the structural formula of CH3CHOHCOOH.

Illustrate the types of isomerism shown by C3H6O3.

13b2 marks

The general structure of polylactic acid is shown below:

polylactic-acid

Draw two possible structures formed from two repeating units. 

Your answer should keep the main polymer chain in the same plane but show the 3D representation of the chiral carbons.

13c1 mark

State, why the polymer formed from the uncontrolled condensation polymerisation of lactic acid, is not a racemate.

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