OCR a Level Chemistry a Multiple Choice Question Quiz (6.3 Analysis)

Multiple Choice Questions (MCQ) topic quiz

6.3 Analysis Instructions and answers for teachers These instructions cover the learner activity section which can be found on page 10. This Lesson Element supports OCR A Level Chemistry A.

When distributing the activity section to the learners either as a printed copy or as a Word file you will need to remove the teacher instructions section.

The Activity This Lesson Element is a teaching and learning resource containing 10 multiple choice questions (MCQs) on the theme of analysis. Some questions might require synoptic thinking, using knowledge and ideas from various topics across the full A Level content.

This resource can be used to test and consolidate understanding at the end of a topic or to revisit and refresh knowledge at a later point in the course.

Learning Outcomes This lesson element relates to the specification learning outcomes 6.3.1(a), 6.3.1(c), 6.3.2(b), 6.3.2(c), 6.3.2(d), 6.3.2(e).

Introduction Multiple choice questions allow rapid coverage of a wide range of sub-topics.

Contrary to a widespread belief among students, multiple choice questions are not necessarily easy – they can be easy, moderate or difficult.

The questions are written so that the incorrect answers are plausible distractors based on common errors or misconceptions.

The questions in this quiz cover topics mainly from specification sections:

6.3 Analysis

Version 1 1 © OCR 2016 Multiple Choice Questions (MCQ) topic quiz – answers

1. In the chromatography plate shown, A and B are standards and C is the test sample.

Which statement is true?

A Sample C has spots which Incorrect, it only matches standard A. match both of the standards

B Standard B has a spot with Rf Incorrect, this has an Rf of 0.4, they have

= 0.6 calculated the Rf incorrectly.

C Sample C contains no more Incorrect, some different compounds can have

than three different the same Rf. components

D The sample contains two Correct answer; there are two spots that do not unidentified components. match either of the standards, so there are (at least) two unknown components.

Your answer D

Version 1 2 © OCR 2016 2. How many peaks would the carbon-13 NMR spectrum of the following compound show?

A 4 Incorrect; they may have counted all the ring carbons as equivalent.

B 6 Correct answer.

C 8 Incorrect; they may have counted each ring carbon individually.

D 9 Incorrect; they have just counted the number of carbons.

Your answer B

3. Which molecule has four carbon environments, four proton environments and a characteristic proton NMR peak at ~9.5 ppm?

A Correct answer

B Incorrect; this would have only three carbon environments and three proton environments.

C Incorrect; this would not have the H–CO peak around 9.5 ppm.

D Incorrect; this would have only three carbon environments and the OH peak would not necessarily be at 9.5 ppm.

Your answer A

Version 1 3 © OCR 2016 4. Three compounds are tested by addition of sodium carbonate and addition of Tollens’ reagent. The results are shown in the table.

Addition of Na2CO3(aq) Addition of Tollens’ reagent

1 no effect silver mirror formed

2 no effect no effect

3 fizzing no effect

Which set of compounds could have produced these results?

A 2-hydroxypentanal 2-bromopropene phenol

Incorrect; phenol would not react with sodium carbonate.

B 3-hydroxybutan-2-one 2-bromopropene phenol

Incorrect; 2-hydroxybutan-2-one would not form a silver mirror, phenol would not react with sodium carbonate.

C 3-hydroxyhexane prop-2-enal butanoic acid

Incorrect; 3-hydroxyhexane would not form a silver mirror, prop-2-enal would form a silver mirror.

D 2-hydroxypentanal 2-chlorobut-2-ene benzoic acid

Correct answer

Your answer D

Version 1 4 © OCR 2016 5. Which of the compounds below is used as a standard in proton NMR and carbon-13 NMR?

A TMS Correct answer

B C6H6 Incorrect, this has no use in NMR.

C CDCl3 Incorrect; they may be confused as this is a common solvent used in NMR.

D D2O Incorrect; they may be confused about the use

of D2O in NMR.

Your answer A

6. A substance is analysed by mass spectrometry and IR spectroscopy. The following incomplete data are collected.

Mass spectrum:

 molecular ion peak at m/z = 128

 fragment ion peak at m/z = 15

IR spectrum:

 sharp peak at 1720 cm–1

 no broad peak around 3200 cm–1

Which substance could the data belong to?

Version 1 5 © OCR 2016 A Incorrect, perhaps a guess. They have not ruled this out using the IR data.

B Incorrect, they may have made an error

calculating the Mr, e.g. missing the hydrogen on the tertiary carbon.

C Correct answer

D This would provide the expected sharp peak in the IR spectrum but also the broad OH peak. They may have rushed their consideration of the IR data.

Your answer C

7. The mass spectrum of this substance shows fragment ions at m/z = 15, 43, 59, 87.

What could be the identity of the substance?

Version 1 6 © OCR 2016 A Incorrect, the double bond means that the fragment ions would have m/z = 41, 59, 87. There may have been errors in calculation or interpretation of the structure.

B This one should be easily ruled out as it does not produce a m/z = 15 fragment ion; it may be a guess.

C This would not produce the fragment ions at m/z = 43 or 59. There may have been errors in finding these fragments, e.g. miscalculating the

mass of the CH3CH2O fragment.

D Correct answer

Your answer D

8. The data table lists the peaks on the proton NMR spectrum for an aromatic compound.

 / ppm Number of protons Splitting pattern 2.16 3 singlet 2.27 6 singlet 6.95 2 doublet 7.00 1 triplet

Which compound could have produced this spectrum?

Version 1 7 © OCR 2016 A Incorrect, this would have 6 different environments as there is no symmetry in the molecule

B Incorrect, the ethyl group would give an obvious triplet and quartet around 2 ppm.

C Correct answer, four environments, two are not aromatic, one with 6 protons and one with three.

D Incorrect, this would have only 2 environments: one aromatic singlet and one singlet around 2 ppm.

Your answer C

Version 1 8 © OCR 2016 9. There are many structural isomers with the molecular formula C4H7Cl, including the following:

Of the isomers shown, determine how many

 show E/Z isomerism

 show optical isomerism.

Show E/Z isomerism Show optical isomerism

Correct answer

Learners often see a pair of CH3 across a double bond and think this excludes E/Z isomers.

This answer combines the errors mentioned for the other options.

Learners may have thought that a double bonded carbon can be a chiral centre.

Your answer A

Version 1 9 © OCR 2016 10. The two isomers shown could be very difficult to distinguish from each other with typical qualitative testing.

Which of the following instrumental techniques would be useful in distinguishing them from each other?

1: mass spectrometry

2: carbon-13 NMR

3: proton NMR

A 1, 2 and 3 Correct answer, each isomer has a different combination of carbon and proton environments and will produce a different fragmentation pattern.

B only 1 and 2 Incorrect, they may think the proton NMR spectra will be difficult to tell apart.

C only 2 and 3 Incorrect; they may think that the isomers shown will produce the same fragmentation pattern.

D only 1 Incorrect; they may think that the isomers will have similar carbon and proton environments.

Your answer A

Version 1 10 © OCR 2016 Thisformative assessment resource has been produced as part of our free Chemistry teaching and learning support package. All the Chemistry teaching and learning resources, including delivery guides, topic exploration packs, lesson elements and more are available on the qualification webpages. If you are looking for examination practice materials, you can find Sample Assessment Materials (SAMs) and a link to the Practice Papers on the qualification webpages: Chemistry A, Chemistry B.

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Version 1 11 © OCR 2016 Multiple Choice Questions (MCQ) topic quiz 6.3 Analysis Learner Activity

1. In the chromatography plate shown, A and B are standards and C is the test sample.

Which statement is true?

A Sample C has spots which match both of the standards

B Standard B has a spot with Rf = 0.6

C Sample C contains no more than three different components

D The sample contains two unidentified components.

Your answer

Version 1 12 © OCR 2016 2. How many peaks would the carbon-13 NMR spectrum of the following compound show?

Your answer

3. Which molecule has four carbon environments, four proton environments and a characteristic proton NMR peak at ~9.5 ppm?

Your answer

Version 1 13 © OCR 2016 4. Three compounds are tested by addition of sodium carbonate and addition of Tollens’ reagent. The results are shown in the table.

Addition of Na2CO3(aq) Addition of Tollens’ reagent

1 no effect silver mirror formed

2 no effect no effect

3 fizzing no effect

Which set of compounds could have produced these results?

A 2-hydroxypentanal 2-bromopropene phenol

B 3-hydroxybutan-2-one 2-bromopropene phenol

C 3-hydroxyhexane prop-2-enal butanoic acid

D 2-hydroxypentanal 2-chlorobut-2-ene benzoic acid

Your answer

B C6H6

C CDCl3

Your answer

6. A substance is analysed by mass spectrometry and IR spectroscopy. The following incomplete data are collected.

Mass spectrum:

 molecular ion peak at m/z = 128

 fragment ion peak at m/z = 15

IR spectrum:

 sharp peak at 1720 cm–1

 no broad peak around 3200 cm–1

Which substance could the data belong to?

7. The mass spectrum of this substance shows fragment ions at m/z = 15, 43, 59, 87.

What could be the identity of the substance?

Your answer

8. The data table lists the peaks on the proton NMR spectrum for an aromatic compound.

 / ppm Number of protons Splitting pattern 2.16 3 singlet 2.27 6 singlet 6.95 2 doublet 7.00 1 triplet

Which compound could have produced this spectrum?

Your answer

9. There are many structural isomers with the molecular formula C4H7Cl, including the following:

Of the isomers shown, determine how many

 show E/Z isomerism

 show optical isomerism.

Your answer

Version 1 18 © OCR 2016 10. The two isomers shown could be very difficult to distinguish from each other with typical qualitative testing.

Which of the following instrumental techniques would be useful in distinguishing them from each other?

1: mass spectrometry

2: carbon-13 NMR

3: proton NMR

A 1, 2 and 3

B only 1 and 2

C only 2 and 3

D only 1

Your answer