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

7 hours110 questions
11 mark

Which of the following shows the correct order of boiling points for pentane, butane and propane?

  • CH3CH2CH3 > CH3CH2CH2CH3 > CH3CH2CH2CH2CH3

  • CH3CH2CH2CH2CH3 > CH3CH2CH2CH3 > CH3CH2CH3

  • CH3CH2CH2CH3 > CH3CH2CH2CH2CH3 > CH3CH2CH3 

  • CH3CH2CH3 > CH3CH2CH2CH2CH3 > CH3CH2CH2CH3  

21 mark

Which of the following statements about propanal, CH3CH2CHO, and propanone, CH3COCH3 is not correct? 

The compounds have:

  • molecular ion peaks at different mass to charge ratios

  • different fragmentation patterns in the mass spectrum

  • absorption in the infrared spectrum due to the carbonyl group

  • a different fingerprint region in the infrared spectrum

31 mark

Nitrogen trichloride has the formula NCl3. A sample was found to contain only 14N, and chlorine atoms with mass numbers 35 and 37. 

Which of the following is an incorrect ion and mass/charge ratio responsible for the molecular ion peaks found in the mass spectrum of nitrogen trichloride? 

 

ion

m/e

A

N(35Cl)3+

119

B

N(35Cl)237Cl+

121

C

N35Cl(37Cl)2+

123

D

N(37Cl)2+

125

    41 mark

    Which of the following cannot be obtained from an infrared spectrum?

    • the molecular mass

    • the presence of C=O bonds

    • the presence of O-H bonds

    • the identity of a compound through comparison with other spectra

    51 mark

    What information can be determined from the infrared spectrum of a molecule?

    • The number of hydrogens

    • The number of hydrogen environments

    • The type of bonds present

    • The relative molecular mass

    61 mark

    Which of the following bonds will produce strong absorptions in the infrared part of the electromagnetic spectrum? 

    I. C-N 

    II. O=O

    III. C=O

    • I and II only  

    • I and III only  

    • II and III only 

    • I, II and III

    71 mark

    Which of the following is true about the fingerprint region in the IR spectrum of alcohols?

    • The fingerprint region is where single bonds can be identified in the IR spectrum  

    • The fingerprint region is unique to every molecule  

    • The fingerprint region does not provide useful information about molecules 

    • A functional group can be identified from the fingerprint region

    81 mark

    Which of the following statements is correct about spectroscopic techniques for organic molecules?

    • Information about bond vibrations can be deduced from mass spectroscopy 

    • The values of carbon–hydrogen bond lengths can be found from 1H NMR spectroscopy 

    • The number of hydrogen atoms can be determined from infrared spectroscopy

    • Information about molecular structure can be found from mass spectroscopy

    91 mark

    In the 1H NMR spectrum of 3-methylbutan-1-ol what is the ratio of the peak areas under each signal?

    • 6 : 1 : 2 : 2 : 1

    • 3 : 3 : 1 : 5 : 1

    • 6 : 1 : 5 : 1

    • 3 : 3 : 1 : 2 : 3

    101 mark

    Which of the following types of spectroscopic identification will involve bond fission in organic molecules?

    • Nuclear magnetic spectroscopy  

    • Infrared spectroscopy 

    • Mass spectrometry 

    • X-ray crystallography

    111 mark

    Which pairs of homologous series do not have the same C:H ratio in their general formulae?

    • aldehydes and ketones

    • alkanes and alkenes

    • carboxylic acids and esters

    • alkenes and aldehydes

    121 mark

    Which of the following molecules are hydrocarbons?

    Four chemical structures labelled 1 to 4: methylbenzene, hexatriene, chloromethane, and bicarbonate ion, each shown in boxes.
    • All

    • 1 and 2

    • 1, 2 and 3

    • 2, 3 and 4

    131 mark

    What is the correct formula for 1-fluoro-3-methylbut-2-ene?

              A           

                         Molecular                          

             CH2FCH2C(CH3)CH3

    B

    Empirical

    C5H9F

    C

    Displayed

    10-1-q3-ib-chemisrey-mcq

    D

    Skeletal

     

    10-1-e-q3-ib-chemistry-mcq

       

      141 mark

      Considering only structural isomers, what is the number of alcohols of each type with the formula C5H12O?

                   

               primary        

             secondary      

            tertiary    

      A

      B

      C

      D

      3

      4

      4

      5

      3

      2

      3

      2

      2

      2

      1

      1

        151 mark

        Which of the following is the displayed formula for ethylamine?

        Four molecular structures labelled A to D, each with carbon, nitrogen, and hydrogen atoms arranged differently, showing various bonding configurations.
          161 mark

          Identify which of the hydrocarbons shown below does not belong in the same homologous series as the other compounds

          • C5H12

          • C6H12

          • C7H16

          • C8H18

          171 mark

          Identify the functional group that is ringed in the molecule shown below:

          Chemical structure of phenylacetone with a benzene ring connected to a two-carbon chain ending in a carbonyl group, circled with dashed lines.
          • hydroxyl

          • carboxyl

          • ether

          • carbonyl

          181 mark

          What is the IUPAC name of the following molecule?

          Chemical structure of 2-chloro-3-methylbutane showing carbon and hydrogen chains with one chlorine atom bonded to the second carbon atom.
          •  2-chloro-3-ethylbutane

          • 3-methyl-4-chloropentane

          • 2-ethyl-3-chlorobutane

          • 2-chloro-3-methylpentane

          191 mark

          What is the IUPAC name of the following molecule?

          Chemical structure of butanoic acid showing a chain of four carbon atoms; with hydrogen and an OH group attached.
          • 3,3-dimethylpropanoic acid

          • 1,1-dimethylpropanoic acid

          • 3-methylbutanoic acid

          • 2-methylbutanoic acid

          201 mark

          Which of the halogenoalkanes shown contains a secondary carbon atom?

          • (CH3)2CHCH2Cl

          • CH3(CH2)3CH2Cl

          • (CH3)3CCl

          • CH3CHClCH2CH3

          21
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          1 mark

          Which molecule contains a chiral carbon?

          • 1-chloro-2-methylbutane

          • 2-methylpropane

          • Butane

          • 2-chloropropane

          22
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          1 mark

          What is name of this compound applying IUPAC rules?

          Ball-and-stick model of ethylene, showing two carbon atoms double-bonded, each bonded to two hydrogen atoms. Carbon is black, hydrogen is white.
          • Trans-pent-2-ene

          • Trans-but-2-ene

          • But-1-ene

          • Cis-but-2-ene

          23
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          1 mark

          Which statement about isomerism is correct?

          • A racemic mixture is optically active 

          • Pent-1-ene exhibits stereoisomerism 

          • 1-bromopropane has two optical isomers 

          • 2-amino-3-methylpentane is a diastereomer

          24
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          1 mark

          Which pair are cis and trans isomers?

          • Two structural formulas of 2,3-dibromobutane showing different stereoisomers. Each carbon is bonded to hydrogen, bromine, and methyl group.
          • Two ethene molecules with a double bond between carbon atoms. Left: CH3 group above right carbon. Right: CH3 group below right carbon.
          • Two structural formulas show isomers of a bromoacetaldehyde molecule. One has bromine on the left carbon, the other on the right.
          • Two structural formulas of dibromoethene isomers showing C=C with opposite and adjacent bromine atoms, indicating geometric isomerism.
          11 mark

          Xylitol is an artificial sweetener used in toothpastes and chewing gum to improve their taste without impairing dental hygiene.

          10-2-m-q1-ib-chemistry-mcqs

          Which functional groups could be produced if Xylitol is oxidised under suitable conditions?

           

          1

                        alkene

          2

                        aldehyde

          3

                        carboxylic acid

          4

                        ketone

          • 1 only

          • 2 only

          • 2, 3 and 4

          • 2 and 4

          21 mark

          Which alcohol is not likely to have a fragment at m/e at 43 in its mass spectrum?

          • (CH3)2CHCH2OH

          • CH3CH(OH)CH2CH2CH3

          • CH3CH2CH2CH2OH

          • CH3CH2CH(OH)CH3

          31 mark

          Which of the compounds shown below is likely to have a fragment at m/e = 45 in its mass spectrum?

          Four chemical structures labelled A, B, C, and D show various organic molecules with carbon, hydrogen, oxygen, and functional groups.
            41 mark

            Chlorine has two isotopes 35Cl and 37Cl.  Assuming in the molecule C4H6Cl4 there is only one hydrogen and one carbon isotope, how many molecular ion peaks will be seen in its mass spectrum?

            • 5

            • 4

            • 3

            • 2

            51 mark

            Bromine exists as two isotopes 79Br and 81Br, which are found in almost equal abundance. 

            Which of the following statements is correct?

            • 79Br is more reactive than 81Br

            • The mass spectrum of C3H7Br has two molecular ion peaks at 122 and 124

            • The atomic radius of 79Br is less than the atomic radius of 81Br

            • The first ionisation energy of 79Br is less than the first ionisation energy of 81Br

            61 mark

            Which alcohol is likely to have a fragment ion at m/e = 31 in its mass spectrum?

            • (CH3)2CHCH2OH

            • CH3CH(OH)CH2CH2CH3

            • CH3CH2CH2C(OH)(CH3)2

            • CH3CH2CH(OH)CH3

            71 mark

            Which pair of compounds would you expect to both have a singly charged peak at m/e = 29 in the mass spectrum? 

            • propan-1-ol and propanal

            • propanal and propanone

            • propan-2-ol and propanal

            • propan-1-ol and propan-2-ol

            81 mark

            The infrared spectrum of a compound is shown below.

            d6mgC1_0_11-1-mcq-q7-medium-ib-chemistry

            Use the infrared absorptions, in wavenumbers, to identify the compound 

            bond

            wavenumber range/ cm-1

            O−H (alcohol)

            3750 – 3200

            C−H (alkane)

            2962 – 2853

            C−H (aldehyde)

            2900 – 2820 and 2775 – 2700

            C═O (aldehyde or ketone)

            1740 - 1680

             

            Which compound is shown by the infrared spectrum?

            • propan-1-ol

            • propan-2-ol

            • propanal

            • propanone

            91 mark

            Which of the ketones listed would not be expected to have a peak in its mass spectrum at m/e = 57?

            • hexan-3-one, CH3CH2CH2COCH2CH3

            • pentan-3-one, CH3CH2COCH2CH3

            • 3-methylbutanone, (CH3)2CHCOCH3

            • butanone, CH3CH2COCH3

            101 mark

            Which of the following statements about the mass spectrum of CH3Br is correct?

            • There is one peak for the molecular ion with an m/e value of 44.

            • There is one peak for the molecular ion with an m/e value of 95.

            • The last two peaks have abundances in the ratio 3:1 and occur at m/e values of 94 and 96.

            • The last two peaks are of equal size and occur at m/e values of 94 and 96.

            111 mark

            Below is a 1H NMR spectrum for an unknown organic compound. The relative areas under the peaks are labelled

            NMR spectrum graph showing peaks labelled as 2H, 1H, 2H, and 3H, along the x-axis from 0 to 11 parts per million (ppm).

            Which of the following compounds could give this spectrum?

            • propan-1-ol, CH3CH2CH2OH

            • propan-2-ol, CH3CH(OH)CH3

            • methyoxyethane, CH3OCH2CH3

            • pentan-2-one, CH3CH2CH2COCH3

            121 mark

            How many structural isomers are there of tribromopropane, C3H5Br3?

            • 4

            • 5

            • 6

            • 7

            131 mark

            How many isomeric esters have the molecular formula C5H10O2?

            • 4

            • 5

            • 9

            • 7

            141 mark

            Which features about the members of a homologous series are correct?

            I. All members have the same general formula

            II. The members have similar chemical properties

            III. The members show a gradual change in physical properties

            • I and II only

            • I and III only

            • II and III only

            • I, II and III

            151 mark

            Octane is a component of petrol or gasoline. Which of the following molecules could be an isomer of octane?

            • CH3CH2CHCHCHCH2(CH3)2

            • (CH3)2CHCH(CH2)2(CH3)2

            • CH3(CH2)5CH3

            • CH3CHCHCH(CH2)2(CH3)2

            161 mark

            Give the name of the following molecule

            Chemical structure of isooctane, a branched hydrocarbon with eight carbon atoms and multiple hydrogen atoms, commonly used as a fuel component.
            • 2,4,4,4-trimethylethylbutane

            • 3,3,5-trimethylhexane

            • 2,4,4-trimethylhexane

            • 1,1,3,3-tetramethylpentane

            171 mark

            How many branched-chain isomers are there which have the molecular formula C5H12?

            • 2

            • 3

            • 4

            • 5

            181 mark

            Study the diagram below and determine which of the three statements are correct

            10-1-m-q8-mcqs-ib-chemistry

            I. A suitable name is hex-4-ene

            II. The empirical formula is CH2

            III. It is an isomer of cyclohexane

            • I and II only

            • I and III only

            • II and III only

            • I, II and III

            191 mark

            Which of the molecules shown below contains an aldehyde functional group?

            • CH3CH2CH2OOCH3 

            • CH3CH2CH2COCH3

            • CH3CH2OCH2CH3

            • CH3CH2CH2CH2CHO

            201 mark

            Which of the halogenoalkanes shown below contains a tertiary carbon atom?

            • CH3CH2CH2Cl

            • CH3CH2CH(CH3)Br

            • C(CH3)3Cl

            • CH3CHBrCH2CH3

            211 mark

            What would be the name of the following compound using IUPAC rules?

            Ball-and-stick model of isopentane molecule, showing carbon (C) and hydrogen (H) atoms connected, illustrating its branched structure.
            • pentane

            • ethylpropane

            • 2-methylbutane

            • 3-methylbutane

            221 mark

            Which two molecules are cis-trans isomers of each other?

            q1_16-2_ib_hl_medium_mcq
            • X and Z

            • X and Y

            • W and Y

            • W and Z

            231 mark

            Which molecule has optical isomers?

            • 2-bromobutane

            • 1,3-dibromopropane

            • 2-chloro-2-methylpropane

            • 3-bromopentane

            241 mark

            What is the name of this molecule?

            q4_20-3_ib_hl_medium_mcq
            • cis-3-methyl-3-hexene

            • trans-4-methyl-4-hexene

            • cis-3-methyl-2-hexene

            • trans-3-methyl-2-hexene

            251 mark

            Which is true about stereoisomerism?

            • But-1-ene has E/Z isomers

            • Butan-2-ol has two enantiomers

            • But-1-ene and but-2-ene are cis-trans isomers

            • Butan-1-ol and butan-2-ol are optical isomers

            11 mark

            The mass spectra of three compounds A, B and C are shown below.

            11-1-mcq-q1-fig-1-hard-ib-chemistry
            Mass spectrum of Compound B showing peaks in relative intensity against mass-to-charge ratio (m/e) from 10 to 90, with highest peaks around 43 and 57.
            Mass spectrum graph for Compound C showing peaks at m/e values with a prominent peak at 57, indicating relative intensity on the y-axis.

            What evidence from the spectra of the three compounds A, B and C, suggests they could be isomers?

            • all show a molecular ion peak at 74

            • all show a molecular ion peak at 13

            • all show a molecular ion peak at 73

            • all show a molecular ion peak at 33

            21 mark

            The infrared spectrum below shows an unknown compound.

            11-1-mcq-q2-hard-ib-chemistry

            bond

            wavenumber range/ cm-1

            C−O; hydroxyl, ester

            1040 – 1300

            C═C; aromatic compound, alkene

            1500 - 1680

            C═O amide

            carbonyl, carboxyl

            ester

            1640 – 1690

            1670 – 1740

            1710 - 1750

            C≡N; nitrile

            2200 – 2250

            C−H; alkane

            2850 – 2950

            N−H; amine, amide

            3300 – 3500

            O−H; carboxyl

            hydroxyl

            2500 – 3000

            3200 - 3600

            Which compound could have produced the infrared spectrum?

            11-1-mcq-q2-ma-hard-ib-chemistry
              31 mark

              The diagram shows an infrared spectrum of a compound.

              11-1-mcq-q3-hard-ib-chemistry

              bond

              wavenumber range/ cm-1

              C−O; hydroxyl, ester

              1040 – 1300

              C═C; aromatic compound, alkene

              1500 - 1680

              C═O amide

              carbonyl, carboxyl

              ester

              1640 – 1690

              1670 – 1740

              1710 - 1750

              C≡N; nitrile

              2200 – 2250

              C−H; alkane

              2850 – 2950

              N−H; amine, amide

              3300 – 3500

              O−H; carboxyl

              hydroxyl

              2500 – 3000

              3200 - 3600

              Which compound would give this spectrum?

              • butanoic acid

              • butanal

              • butan-1-ol

              • 1-bromobutane

              41 mark

              Which of the following infrared spectra could show a carboxylic acid?

              Graph showing transmittance (%) versus wavenumber (cm⁻¹), with peaks and valleys from 4000 to 400 cm⁻¹, labelled "A" on the left side.
              Graph showing transmittance percentage versus wavenumber in cm⁻¹, with peaks and troughs indicating varying transmittance from 4000 to 400 cm⁻¹.
              11-1-mcq-q4-fig-3-hard-ib-chemistry
              Graph showing transmittance percentage versus wavenumber (cm⁻¹) ranging from 4000 to 400. Peaks and troughs indicate absorbance at specific wavelengths.

              Bond

              Wavenumber range/ cm-1

              C−O; hydroxyl, ester

              1040 – 1300

              C═C; aromatic compound, alkene

              1500 - 1680

              C═O amide

              carbonyl, carboxyl

              ester

              1640 – 1690

              1670 – 1740

              1710 - 1750

              C≡N; nitrile

              2200 – 2250

              C−H; alkane

              2850 – 2950

              N−H; amine, amide

              3300 – 3500

              O−H; carboxyl

              hydroxyl

              2500 – 3000

              3200 - 3600

                5
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                1 mark

                A compound XFn is a fluoride of another halogen, X, and it is known that n > 1. The highest m/e peak in the mass spectrum of XFn is assigned to the parent ion and comes as a single peak at m/e = 222. 

                Which of the following statements is incorrect?

                • n = 5

                • the compound could contain bromine

                • there are no isotopes of X or F

                • the compound is a fluoride of iodine

                61 mark

                An organic compound is analysed by mass spectrometry and infrared spectroscopy. The following data is obtained.

                mass spectrometry

                infrared spectroscopy

                molecular ion peak at m/e = 128

                sharp peak at 1720 cm-1

                fragment ion peak at m/e = 15

                no broad peak around 3200 cm-1

                 

                Bond

                Wavenumber range/ cm-1

                C−O; hydroxyl, ester

                1040 – 1300

                C═C; aromatic compound, alkene

                1500 - 1680

                C═O amide

                carbonyl, carboxyl

                ester

                1640 – 1690

                1670 – 1740

                1710 - 1750

                C≡N; nitrile

                2200 – 2250

                C−H; alkane

                2850 – 2950

                N−H; amine, amide

                3300 – 3500

                O−H; carboxyl

                hydroxyl

                2500 – 3000

                3200 - 3600

                 

                Which of the following compounds could be consistent with the data given?

                11-1-mcq-q6-hard-ib-chemistry
                  71 mark

                  What does the 1H NMR spectrum below tell you about a molecule?

                  NMR spectrum showing one tall peak at 1.5 ppm on the horizontal axis labelled "Chemical shift / ppm," with values ranging from 10 to 0 ppm.
                  • There is only one isotope of hydrogen present in the molecule

                  • The molecule is a hydrocarbon

                  • There is only one hydrogen atom in the molecule

                  • There is only one hydrogen environment in the molecule

                  81 mark

                  How many peaks would you expect to see in a 1H NMR spectrum of methylbenzene?

                  Chemical structure of toluene, showing a hexagonal benzene ring with three alternating double bonds and a methyl group (CH3) attached.
                  • 3

                  • 4

                  • 5

                  • 6

                  91 mark

                  How many isomers, including structural and stereoisomers, with the formula C5H10 have structures that involve π bonding?

                  • 3

                  • 4

                  • 5

                  • 6

                  101 mark

                  Study the formulae shown below and determine which molecules are isomers of each other

                  I. CH3(CH2)3CH2CH3

                  II. (CH3)2CHCH2CH3

                  III. CH3CH(CH3)CH2CH2CH3

                  • I and II only

                  • I and III only

                  • II and III only

                  • I, II and III

                  111 mark

                  What is the correct condensed structural formula for 2,2-dibromo-4-methylhexane?

                  • CH3CBr2CH(CH3)CH2CH2CH3

                  • CH3CHBrCBr(CH3)CH2CH2CH3

                  • CH3CBr2CH2CH(CH3)CH2CH3

                  • CH3CHBrCH(CH3)CHBrCH2CH3

                  121 mark

                  What is the correct IUPAC name for the molecule shown?

                  Chemical structure of ethyl acetate showing carbon, hydrogen, and oxygen atoms bonded in a linear arrangement with single and double bonds.
                  • ethoxyethane

                  • methoxyethane

                  • propanone

                  • propanal

                  131 mark

                  Which of the molecules shown below is not an isomer of pentan-2-ol?

                  • pentan-1-ol

                  • 2-methylbutan-2-ol

                  • 2-methylpentan-2-ol

                  • pentan-3-ol

                  141 mark

                  Which of the following pairs are functional group isomers?

                  I. CH3CH(OH)CH2CH2CH3 and CH3CH2CH(OH)CH2CH3

                  II. CH3CH2CH2COOH and HCOOCH2CH2CH3

                  III. CH3CH2CH2OH and CH3OCH2CH3

                  • I and II only

                  • I and III only

                  • II and III only

                  • I, II and III

                  151 mark

                  What is the correct name of the following molecule using IUPAC rules?

                  Chemical structure diagram of ethanol, showing carbon (C), hydrogen (H), and oxygen (O) atoms connected in a linear arrangement.
                  • propyl methanoate

                  • methyl propanoate

                  • methoxypropane

                  • butoxymethanal

                  161 mark

                  What types of isomerism can the following molecule show?

                  Skeletal formula of propyl ethanoate, showing carbon, hydrogen, and oxygen atoms bonded in a chain, representing a simple organic ester.

                  I. Branch-chain

                  II. Positional 

                  III. Functional group

                  • I and II only

                  • I and III only

                  • II and III only

                  • I, II and III

                  17
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                  1 mark

                  How many dimethyl cyclopentane isomers are disubstituted and have the cyclopentane structure? 

                  • 3

                  • 4

                  • 5

                  • 6

                  18
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                  1 mark

                  Which structure is the correct cis trans isomer of trans-1,2-dibromocyclobutane? 

                  • Cyclohexane molecule with two bromine atoms attached on one carbon and six hydrogen atoms on others, depicted in a 3D stick model.

                     

                  • Chemical structure of bicyclo[2.2.1]heptane with two bromine atoms and eight hydrogen atoms attached, forming a bridged cyclic compound.

                     

                  • Chemical structure of dibromocyclohexane showing a hexagonal ring with two bromine atoms and multiple hydrogen atoms attached.

                     

                  • Chemical structure of trans-1,2-dibromocyclohexane, showing a six-carbon ring with two bromine atoms on adjacent carbons and several hydrogen atoms.

                     

                  19
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                  1 mark

                  Which molecule has a chiral centre? 

                  • CH3OCH2CH3

                  • CH3CH2CHO

                  • CH3CH(NH2)CH3

                  • CH3CH(OH)CH2CH3

                  20
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                  1 mark

                  Arthrinin-F is a compound isolated from fungus.

                  Chemical structure diagram of Quinic acid, showing a six-membered ring with three hydroxyl groups and various bonds.

                  What is the correct number of chiral carbons in the structure?

                  • 2

                  • 3

                  • 4

                  • 5