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| Series | Paper | Q | What it asks |
|---|---|---|---|
| June 2024 | Paper 3 | 5(b)(ii) | The student is provided with further information about compounds F–I. Use this further information and the student’s observations in Table 5.1 to answer the following. |
| November 2021 | Paper 2 | 21 | Compounds D, E and F are isomers with the molecular formula C5H10O. Analyse the observations and results to identify the structures of D, E and F. |
| June 2017 | Paper 3 | 5(b) | The structures for six naturally occurring organic compounds with pleasant smells, B–G, are Explain how chemical tests would allow each compound to be distinguished from the other |
![(b) A chemical test is carried out which gives a positive result for all three compounds.
Suggest the reagent and observation of this chemical test.
Reagent ............................................................................................................................................
Observation ......................................................................................................................................
[2]](/img/JUN25_H4322/JUN25_H4322_21(b).webp)
The majority of candidates scored both marks here. A few lost the second mark for just saying ‘turned orange’ without ppt. Some gave tests in (c) here as well but were usually consistent showing all three reacting in the table.
Skills: PAG7 Qualitative analysis of organic functional groups
![(c) A student is provided with three unlabelled sample tubes, containing either pyruvic acid,
methylglyoxal or acetol.
The student carries out three chemical tests on each sample.
Complete the table with the expected observations, including ‘no change’ where appropriate.
Expected observations
Chemical test
Pyruvic acid Methylglyoxal Acetol
Tollens’ reagent
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Na2CO3(aq)
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Cr2O7 2–(aq)/H+(aq)
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[3]](/img/JUN25_H4322/JUN25_H4322_21(c).webp)
Very few candidates did not score any marks for this observation question. Common errors included: • gas/CO2 formed for the reaction with carbonate. The observation was needed • no reaction for methylglyoxal with dichromate, as they had not realised aldehydes will react as well as primary and secondary alcohols • positive test for all three with dichromate − often linked with incorrect answer in Question 9 • white precipitate with the reaction with carbonate • bubbles with acetol with carbonate (presence of C=O and O-H leading to possible confusion with an acid?). Candidates gave a range of responses for the reactions with no change, e.g. ‘no silver mirror formed’, ‘stays orange or ‘nothing’, these were still accepted but for clarity candidates should respond as the question asks.
Skills: PAG7 Qualitative analysis of organic functional groups
![22 This question is about organic acids.
α-Amino acids have the general formula RCH(NH2)COOH.
(a) Compound S is made of two α-amino acids bonded together.
Compound S is hydrolysed into its component α-amino acids.
The resulting mixture is analysed using TLC to produce a chromatogram:
solvent front
start line
The R group and the Rf value is shown for some α-amino acids.
R group Rf value
–H 0.18
–CH3 0.25
–CH2CH(CH3)2 0.64
–CH(CH3)2 0.77
(i) Determine the Rf values of the two α-amino acids in the chromatogram.
[1]](/img/JUN25_H4322/JUN25_H4322_22(a)(i).webp)
The majority were able to correctly calculate Rf values and gain a mark here. A few did not gain marks for calculator errors (they had corrected measurements but gave the wrong answer) or for incorrect measurements, e.g. from the bottom of the TLC rather than the start line.
Skills: M0.2 Use ratios, fractions and percentages; M3.1 Translate information between graphical, numerical and algebraic forms; PAG6 Synthesis of an organic solid
![(ii) Compound S has two possible structures.
Draw both of these structures.
[2]](/img/JUN25_H4322/JUN25_H4322_22(a)(ii).webp)
Many candidates found this question tricky with only some able to score both marks. The most common correct responses were the dipeptides given as the first two structures on the mark scheme. The acid anhydride structure was less commonly seen and the cyclic peptide structure was rare. Candidates who got this response wrong often gave just the two amino acids identified from their Rf values in part (a)(i), forgetting that the amino acids needed to be joined together to create compound S. Some included an O in their amide bond i.e. -COONH- and lost both marks. Some recognised that the central C in an amino acid is chiral so drew stereoisomers. Some added an extra CH2 in the side chain of CH(CH3)2 but ECF was given for the second structure. Around half of all candidates didn’t score any marks here with some not even attempting this question at all.
![(b) Nuromol tablets are used to relieve pain.
Nuromol tablets contain a mixture of ibuprofen and paracetamol.
The structures of ibuprofen and paracetamol are shown.
H3C OH
CH2
O O
CH
C C
CH3
OH H3C N
CH
H
CH3
Ibuprofen Paracetamol
A student carries out an investigation to determine the mass of ibuprofen and the mass of
paracetomol in one nuromol tablet.
• Ibuprofen reacts with aqueous sodium carbonate, Na2CO3(aq), to produce a gas.
2RCOOH + Na2CO3 2RCOONa + CO2 + H2O
• Paracetamol does not react with Na2CO3(aq).
(i) Why does paracetamol not react with Na2CO3(aq)?
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This question was answered well, with most candidates identifying that ibuprofen contains a phenol group or that it does not contain a carboxylic acid. A named functional group was required in the answer. Some described phenol incorrectly as not being an acid and this was not credited. It was rare for incorrect functional groups to be seen in candidate responses.
![3 A student investigates the rate of hydrolysis of different iodoalkanes using aqueous silver nitrate
in ethanol.
What colour of precipitate is seen?
A Brown
B Cream
C White
D Yellow
Your answer
[1]](/img/JUN24_H4322/JUN24_H4322_03.webp)
D
Most correctly identified the colour of the precipitate as yellow, D. The most common incorrect response was brown, A, possibly linking to the colour of iodine.
Skills: PAG7 Qualitative analysis of organic functional groups
![5 Geraniol, shown below, is a component in many natural oils.
OH
Geraniol
Which pair of reagents identifies both functional groups in geraniol?
A Acidified dichromate(VI) and 2,4-dinitrophenylhydrazine.
B Bromine water and 2,4-dinitrophenylhydrazine.
C Bromine water and acidified dichromate(VI).
D Tollens’ reagent and aqueous silver nitrate in ethanol.
Your answer
[1]](/img/JUN24_H4322/JUN24_H4322_05.webp)
C
The majority of candidates were able to correctly identify the two functional groups and the correct corresponding test i.e. alkene using bromine water and primary alcohol using 2,4-dinitrophenylhydrazine. The most common incorrect response was B.
Skills: PAG7 Qualitative analysis of organic functional groups
![13 A sample containing a mixture of 3 components, X, Y and Z, is analysed using gas
chromatography.
The gas chromatogram below is obtained.
The relative peak areas of X, Y and Z are included.
Z
Relative peak areas
X = 1.0
1000 Y
Y = 3.5
Z = 5.5
X
Recorder response
500
0
0 5 10 15
Time / min
Which statement(s) is/are true?
1 The peak for component X shows the mass of one mole.
2 Component Y stays in the column for longer than component X.
3 Component Z consists of more than half of the sample.
A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1
Your answer
[1]](/img/JUN24_H4322/JUN24_H4322_13.webp)
C
More than half of candidates were able to give C as the correct answer recognising that Statements 2 and 3 are correct. Some felt that Statement 1 was also correct giving A or B as the answer – relative peak area is not the same as the mass of 1 mole. Some were not able to relate the peak area to amount of compound present, so did not pick Statement 3 as one of the true statements, giving B or D.
Skills: M0.2 Use ratios, fractions and percentages; M3.1 Translate information between graphical, numerical and algebraic forms
![5 This question is about the analysis of organic compounds.
(a) A student investigates the alkaline hydrolysis of 1-bromopropane as outlined below.
Step 1 The student adds 1-bromopropane to an excess of aqueous potassium hydroxide,
KOH(aq), in a pear-shaped flask.
Step 2 A TLC chromatogram is run using propan-1-ol and the reaction mixture.
Step 3 The reaction mixture is refluxed.
A TLC chromatogram of the reaction mixture is run every 10 minutes.
The TLC chromatograms are shown below.
Before reflux After 10 minutes After 20 minutes After 30 minutes
solvent
front
origin
propan-1-ol reaction mixture propan-1-ol reaction mixture propan-1-ol reaction mixture propan-1-ol reaction mixture
(i) Determine the Rf value of propan-1-ol.
Show your working.
Rf = ................... [1]](/img/JUN24_H4323/JUN24_H4323_05(a)(i).webp)
Candidates are well versed with calculating an Rf value, with nearly all candidates obtaining a value in the acceptable range of 0.12–0.18.
Skills: M0.2 Use ratios, fractions and percentages; M3.1 Translate information between graphical, numerical and algebraic forms; PAG6 Synthesis of an organic solid
![(iii) A student investigates the alkaline hydrolysis of 1-chloropropane using the same method as for
1-bromopropane.
Predict, with reasons, how the appearance of the reaction mixture in the chromatogram produced
after 20 minutes would be different when 1-chloropropane is used instead of 1-bromopropane.
Suggest why propan-1-ol is run alongside the reaction mixture.
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This novel question assessed whether candidates realised why chemists used TLC when carrying out organic reactions. A good response would identify the following key features after 20 minutes: • The C–Cl bond energy is greater than C–Br and so the reaction would be slower. • The haloalkane spot would be larger and the propan-1-ol spot smaller. • The propan-1-ol is spotted on the chromatogram to monitor the progress of the reaction. The question differentiated very well between candidates, but many did not seem to know where to start with many candidates not scoring any marks. This suggested that candidates recognised chromatography as a technique but did not appreciate its relevance in organic chemistry. Some candidates referred to pigments, recalling their early chromatography experiments in finding the colours in ink.
Skills: PAG6 Synthesis of an organic solid
![(ii)* The student is provided with further information about compounds F–I.
• They all have the molecular formula C5H10O.
• One of the compounds is alicyclic.
• The other compounds are unbranched.
Use this further information and the student’s observations in Table 5.1 to answer the following.
• How do the observations provide evidence for the possible functional groups in
compounds F–I?
• Suggest a possible structure for each of the compounds F–I.
Show your reasoning. [6]
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Extra answer space if required.
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This Level of Response question was answered well with many candidates identifying compounds F–I correctly to reach Level 3. Structures were usually shown skeletally and this practice is to be recommended. Not only is it far quicker and clearer, it eliminates writing every atom in a displayed or structural formula. Some candidates were not given marks for missing hydrogen atoms or for ‘sticks’ being shown. In these structures, the chemical meaning of a stick is a terminal CH3 group. Candidates were also asked to show how the results of the chemical tests helped the identification of the unknown compounds and this formed the basis of the communication strand of the LOR mark. Candidates answered this part of the analysis extremely well and most were given marks for their good communication skills. This question differentiated very well between well-prepared and less confident candidates. The latter often did not know how the results of these organic tests can be used to identify the functional groups present. It was common for such candidates to identify only one of the four compounds, scoring within Level 1 only. This exemplar is concise and very clear. The candidate has clearly linked the result of each test to the functional groups that must be present. The candidate has drawn skeletal formulae and clearly has experimented with many possible structures before deciding on which must be correct. Notice that the candidate has crossed out the structures that they have rejected. This is an important exam technique – if two structures are drawn, with one correct and the other incorrect, the correct structure cannot be given marks. The response is clearly at Level 3 for the four correct structures and the good communication ensures that the communication strand can be given. This response received all 6 marks.
Skills: PAG7 Qualitative analysis of organic functional groups
![2 Which compound reacts with 2,4-dinitrophenylhydrazine but does not react with Tollens’
reagent?
A C6H5COCOOH
B C6H5CH(OH)CHO
C CH3COCHO
D CH3CH2CH(OH)CH3
Your answer
[1]](/img/JUN23_H4322/JUN23_H4322_02.webp)
A
Drawing out the structures often helped candidates to identify each functional group and therefore spot the ketone which is key to correctly answering this question.
![18 This question is about carbonyl compounds.
(a) (i) Describe a chemical test to confirm the presence of a carbonyl group.
How could the product of this test be used to identify the carbonyl compound?
Your answer should not include spectroscopy.
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...................................................................................................................................... [3]](/img/JUN22_H4322/JUN22_H4322_18(a)(i).webp)
The use of 2,4-dinitrophenylhydrazine as a test for the carbonyl group is well known by candidates at this level. The majority of the cohort correctly identified this test and the subsequent analysis of the melting point of the products as a method of identifying each compound. Lower ability candidate responses made reference to analysis of the boiling points or omitted the reference to analysis of the melting points.
Skills: PAG6 Synthesis of an organic solid; PAG7 Qualitative analysis of organic functional groups
![(ii) Describe a chemical test that would identify whether a carbonyl compound is an
aldehyde.
Your answer should include the reagent and observations.
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...................................................................................................................................... [1]](/img/JUN22_H4322/JUN22_H4322_18(a)(ii).webp)
Almost all candidates were able to correctly describe the use of Tollens’ reagent as a test for an aldehyde fictional group
Skills: PAG7 Qualitative analysis of organic functional groups
![20 This question is about the chemistry of aromatic compounds.
(a) Compounds J, K and L, shown below, are structural isomers.
CH3
CH2CH2OH OH H3C OH
CH3 CH3
Compound J Compound K Compound L
(i) What chemical test(s) could be used to confirm the presence of the phenol group in
compounds K and L?
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...................................................................................................................................... [1]](/img/JUN22_H4322/JUN22_H4322_20(a)(i).webp)
Few candidates knew the test for a phenol group. Frequent incorrect responses involved the production of a gas with a carbonate or stating that bromine water is decolourised but failing to state that a white precipitate is also formed. A significant number of candidates also stated that the reaction with sodium hydroxide confirms the presence of the phenol group.
Skills: PAG7 Qualitative analysis of organic functional groups
![10 A TLC chromatogram for two compounds is shown below.
solvent front
origin
What is the Rf value for the compound that is most strongly adsorbed onto the stationary phase?
A 0.25
B 0.33
C 0.69
D 0.78
Your answer
[1]](/img/NOV21_H4322/NOV21_H4322_10.webp)
A
![21* Compounds D, E and F are isomers with the molecular formula C5H10O.
One of the compounds is alicyclic.
A student carries out test-tube tests on the compounds.
The observations are shown below.
Compound 2,4-DNP H+/Cr2O7 2–, reflux Bromine water
D No change Green solution No colour change
Orange
E No colour change No colour change
precipitate
Orange
F No colour change No colour change
precipitate
13C NMR spectrum of D Compound D has 3 peaks at δ / ppm: 24, 36, 73.
1H NMR spectra of E and F The integration data has been omitted.
Compound E
3 2 1 0
chemical shift, δ / ppm
Compound F
Expansion of multiplet
3 2 1 0
chemical shift, δ / ppm
Analyse the observations and results to identify the structures of D, E and F.
Explain your reasoning. [6]
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Additional answer space if required.
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Skills: M3.1 Translate information between graphical, numerical and algebraic forms; PAG7 Qualitative analysis of organic functional groups
![13 Which statement(s) is/are correct for gas chromatography?
1 The components in a mixture can be identified from their retention time.
2 The relative peak areas give the proportions of components in a mixture.
3 Calibration curves are used to confirm the concentrations of components in a mixture.
A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1
Your answer
[1]](/img/NOV20_H4322/NOV20_H4322_13.webp)
A
![(b) Describe suitable chemical tests, with observations, that would confirm the presence of the
functional groups in F and G.
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Question 19(b) Candidates who found this question difficult often did not give a response that would identify all three of the functional groups (aldehyde, ketone and alkene).
Skills: PAG7 Qualitative analysis of organic functional groups
![(b) Geraniol and citronellal, shown below, are isomers present in ‘citronella oil’, used as an insect
repellent.
OH
O
Geraniol Citronellal
• Geraniol and citronellal are structural isomers of each other.
• They also show stereoisomerism.
(i) Describe how the observations from a chemical test would distinguish between geraniol
and citronellal.
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...................................................................................................................................... [2]](/img/JUN19_H4322/JUN19_H4322_16(b)(i).webp)
Almost all candidates were able to describe a suitable test to distinguish between geraniol and citronellal and most scored both marks. The most common choice was to use Tollens’ reagent to identify the aldehyde group in citronellal by the formation of a silver mirror. Other candidates opted for 2,4- dinitrophenylhdrazine to differentiate the carbonyl compound from the alcohol.
Skills: PAG7 Qualitative analysis of organic functional groups
![(b) The student is provided with another amino acid.
The student attempts to identify the unknown amino acid using chromatography.
The student obtains two TLC chromatograms of the unknown amino acid and the four amino
acids in Table 17.1, using two different solvents, W and X.
solvent front
origin
unknown ala ser leu gly unknown ala ser leu gly
amino amino
acid acid
Solvent W Solvent X
(i) What is the Rf value of serine (ser) in solvent W?
Rf = ......................................................... [1]](/img/JUN19_H4322/JUN19_H4322_17(b)(i).webp)
Candidates are familiar with the calculation of Rf values and this question was answered very well. Although almost all candidates showed appropriate working as part of their response some candidates gave the final answer to only one significant figure and did not receive credit. Candidates were expected to give their answer to a number of significant figures appropriate to the measurements they had made, so a minimum of two significant figures was expected. The mark scheme allowed a response within a range, rather than a specific value, and most candidates scored in this part.
Skills: M3.1 Translate information between graphical, numerical and algebraic forms; PAG6 Synthesis of an organic solid
![(ii) Analyse the chromatograms to identify the unknown amino acid.
Explain your reasoning.
Name of unknown amino acid ...........................................................................................
Explanation .......................................................................................................................
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A LEVEL CHEMISTRY A Examiners’ report H432/02 Summer 2019 series Version 1 H432 For first teaching in 2015 www.ocr.org.uk/science Contents Introduction .............................................................................................................................................. 4 Paper 2 series overview ........................................................................................................................... 5 Section A overview ................................................................................................................................... 6 Question 3 ............................................................................................................................................ 6 Question 4 ............................................................................................................................................ 6 Question 5 ............................................................................................................................................ 7 Question 10 .......................................................................................................................................... 8 Question 12 .......................................................................................................................................... 9 Question 13 ........................................................................................................................................ 10 Question 14 ........................................................................................................................................ 10 Question 15 ........................................................................................................................................ 11 Section B overview ................................................................................................................................. 12 Question 16 (a) (i) ............................................................................................................................... 12 Question 16 (a) (ii) .............................................................................................................................. 12 Question 16 (b) (i) ............................................................................................................................... 13 Question 16 (b) (ii) .............................................................................................................................. 14 Question 16 (b) (iv) ............................................................................................................................. 14 Question 16 (b) (v) .............................................................................................................................. 15 Question 17 (a) (i) ............................................................................................................................... 17 Question 17 (a) (ii) .............................................................................................................................. 19 Question 17 (b) (i) ............................................................................................................................... 20 Question 18 (a) (i) ............................................................................................................................... 21 Question 18 (a) (ii) .............................................................................................................................. 22 Question 18 (b) ................................................................................................................................... 23 Question 18 (c) ................................................................................................................................... 23 Question 18 (d) ................................................................................................................................... 24 Question 18 (e) (i) ............................................................................................................................... 24 Question 18 (e) (ii) .............................................................................................................................. 26 Question 19 (a) (i) ............................................................................................................................... 27 Question 19 (a) (ii) .............................................................................................................................. 29 Question 19 (b) (i) ............................................................................................................................... 30 Question 19 (b) (iii) ............................................................................................................................. 32 Question 19 (b) (iv) ............................................................................................................................. 34 Question 20 (a) (i) ............................................................................................................................... 36 Question 20 (a) (ii) .............................................................................................................................. 37 Question 20 (a) (iii) ............................................................................................................................. 37 Question 20 (b) (i) ............................................................................................................................... 38 Question 21 ........................................................................................................................................ 39 Introduction Our examiners’ reports are produced to offer constructive feedback on candidates’ performance in the examinations. Question 17 (b) (i) Candidates are familiar with the calculation of Rf values and this question was answered very well.
Skills: M3.1 Translate information between graphical, numerical and algebraic forms; PAG6 Synthesis of an organic solid
![(c) Compound B is a structural isomer of ester A.
• Compound B reacts with aqueous sodium carbonate.
• The 13C NMR spectrum of B has 4 peaks.
Draw a possible structure for compound B.
[1]](/img/JUN19_H4322/JUN19_H4322_18(c).webp)
This question required candidates to use both pieces of information to deduce that B was a carboxylic acid with two equivalent carbon atoms. Many candidates were able to suggest a suitable structure. However some candidates did not use all the information and it was common to see responses that showed an ester or a straight chain carboxylic acid.
![(iii) Name the functional group responsible for the acidity of chloroxylenol and describe a
simple test which would confirm the presence of this group.
Functional group ................................................................................................................
Test ....................................................................................................................................
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Most candidates identified the phenol functional group but a satisfactory test proved to be far more difficult. Many candidates identified that there would be no effervescence with sodium carbonate but it was common that the pH being less than 7 was often not seen. Neutralisation with sodium hydroxide was often seen but with no observation. Although not in the specification, the reaction with bromine to produce a white precipitate was often seen as an acceptable alternative test for the phenol group.
Skills: PAG7 Qualitative analysis of organic functional groups
![(ii) Analyse the information to identify E, F and G.
Show your working.
[3]](/img/JUN18_H4322/JUN18_H4322_19(c)(ii).webp)
This question, requiring candidates to analyse the information to identify compounds E, F and G, discriminated well. Many candidates deduced that G was a silver halide but not all provided working to back up their choice of AgBr. Some candidates appeared to guess and AgCl was commonly seen. Some candidates used the molar mass of F provided to deduce the molecular formula of C4H10O but lower ability responses did not process this further. Higher ability candidates identified F as butan-2-ol, showing the chiral carbon clearly. Other alcohols were also seen including butan-1-ol and methylpropan- 2-ol. The highest ability candidates linked all the information and provided a structure for E that was consistent with their suggestions for F and G.
Skills: M0.2 Use ratios, fractions and percentages; M2.2 Change the subject of an equation
![(b) A student plans to carry out some chemical tests on both cinnamaldehyde and
methylcinnamaldehyde.
CHO CHO
cinnamaldehyde methylcinnamaldehyde
(i) Suggest a suitable chemical test to confirm that both compounds contain an unsaturated
carbon chain.
Your answer should include the reagent and observations.
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...................................................................................................................................... [1]](/img/JUN18_H4322/JUN18_H4322_20(b)(i).webp)
Almost all candidates were able to correctly describe the use of bromine as a test for an unsaturated chain.
Skills: PAG7 Qualitative analysis of organic functional groups
![(ii) Describe a chemical test to confirm that both compounds contain an aldehyde functional
group.
Your answer should include the reagent and observations.
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...................................................................................................................................... [1]](/img/JUN18_H4322/JUN18_H4322_20(b)(ii).webp)
Almost all candidates were able to correctly describe the use of Tollens’ reagent as a test for an aldehyde functional group.
Skills: PAG7 Qualitative analysis of organic functional groups
![(iii) Describe a chemical test to confirm that cinnamaldehyde and methylcinnamaldehyde
contain a carbonyl group.
How could the products of this test be used to distinguish between the two compounds?
Your answer should not include spectroscopy.
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The use of 2,4-dinitrophenylhydrazine as a test for the carbonyl group is well known by candidates at this level. The majority of the cohort correctly identified this test and the subsequent analysis of the melting point of the products as a method of identifying each compound. Lower ability candidate responses made reference to analysis of the boiling points of the cinnamaldehyde and methylcinnamaldehyde as a means of identification.
Skills: PAG6 Synthesis of an organic solid; PAG7 Qualitative analysis of organic functional groups
![(c) A cosmetic product containing four esters, J, K, L and M, is analysed by gas chromatography
and mass spectrometry. The results are shown below.
Gas chromatogram
M
5.9
K
J
4.3
4.2
L
1.0
0 1 2 3 4 5
retention time / minutes
The numbers by the peaks are the relative molar proportions of the compounds in the mixture.
Mass spectrometry
ester m/z of molecular ion peak
J 152
K 166
L 180
M 180
(i) The concentration of ester K in the cosmetic product is 9.13 × 10−2 g dm−3.
Using the results, calculate the concentration, in mol dm−3, of ester M in the cosmetic
product.
Give your answer to two significant figures.
concentration of ester M = .......................................... mol dm−3 [2]](/img/JUN18_H4322/JUN18_H4322_21(c)(i).webp)
This question required candidates to apply their knowledge of gas chromatography and the mole to solve this problem. Most candidates recognised the need to use the relative peak areas to determine the relative proportion of M. Many also realised that division by the molar mass was required to ensure the final answer was given in mol dm–3. However, some used molar mass of M rather than K in this step, leading to an answer of 7.0 × 10–4 mol dm–3. Answer = 7.5 × 10–4 mol dm–3
Skills: M0.2 Use ratios, fractions and percentages; M1.1 Use an appropriate number of significant figures; M3.1 Translate information between graphical, numerical and algebraic forms
![(b) Qualitative tests are carried out on the aromatic compound. The results are shown below.
Test Acidity Na2CO3(aq) 2,4-DNP Tollens’ reagent
No observable No observable
Observation pH = 5 Orange precipitate
change change
Determine the functional groups in the compound. Explain your reasoning.
Functional groups .....................................................................................................................
Explanation ...............................................................................................................................
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............................................................................................................................................. [3]](/img/JUN17_H4322/JUN17_H4322_20(b).webp)
Skills: PAG7 Qualitative analysis of organic functional groups
![(b)* The structures for six naturally occurring organic compounds with pleasant smells, B–G, are
shown below. The common names in brackets relate to their source and smell.
OH
O
B C
(linalool) (citral)
O
OH
D
(geraniol)
E
(camphor)
O
OH
F G
(menthol) (ionone)
Explain how chemical tests would allow each compound to be distinguished from the other
compounds.
In your answer, include essential details for all test procedures and observations.
Details of apparatus and quantities are not required.
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............................................................................................................................................. [6]](/img/JUN17_H4323/JUN17_H4323_05(b).webp)
Skills: PAG7 Qualitative analysis of organic functional groups
Dropping marks on calculations, mechanisms or the six-markers? Book a trial session with a specialist OCR chemistry tutor.
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