Which statement is correct for a pair of enantiomers under the same conditions?

A.  A racemic mixture of the enantiomers is optically active.

B.  They have the same chemical properties in all their reactions.

C.  They have the same melting and boiling points.

D.  They rotate the plane of plane-polarized light by different angles.

C

Which molecule has an enantiomer?

A.  ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_3$

B.  ${\mathrm{CH}}_2\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}={\mathrm{CH}}_2$

C.  ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}=\mathrm{CHBr}$

D.  ${\mathrm{CH}}_3{\mathrm{CHBrCH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$

D

The majority of candidates could correctly identify the molecule which has an enantiomer.

Which is correct for the conversion of propanal to propyl methanoate?

D

What will be the major product in the reaction between but-1-ene and $\mathrm{Hbr}$?

A.  2-bromobut-1-ene

B.  1-bromobut-1-ene

C.  2-bromobutane

D.  1-bromobutane

C

The vast majority selected the correct product for the reaction of but-1-ene and HBr although quite a few selected the minor product of 1-bromobutane.

Which molecule is chiral?

A.     2-chlorobutane

B.     2,2-dichloropentane

C.     Propan-2-amine

D.     4-hydroxybutanoic acid

A

Which is most likely to hydrolyse via a S_N1 mechanism?

A.  CH₃CHBrCH₂CH₃

B.  (CH₃)₂CHBr

C.  (CH₃)₃CBr

D.  CH₃CH₂CH₂CH₂Br

C

Which compound rotates the plane of plane-polarized light?

A.  CH₃C(CH₃)ClCH₃

B.  CH₃CH₂CHClCH₃

C.  CH₃C(Cl)₂CH₃

D.  CH₃CClBrCH₃

B

In which order should the reagents be used to convert benzene into phenylamine (aniline)?

C

Which compound shows cis-trans isomerism?

A.  CH₃CH=CCl₂

B.  CCl₂=CH₂

C.  

D.  

D

What is the product of the reaction of benzene with a mixture of concentrated nitric and sulfuric acids?

C

Which reagents are needed to convert nitrobenzene to phenylamine in 2 steps?

D

Which molecule contains a chiral carbon?

A.     CH₃CH₂CHBrCH₂CH₃

B.     CH₃CH₂CHBrCH₃

C.     CH₂BrCH(CH₃)CH₂Br

D.     CH₃CH₂CH₂CH₂CH₂Br

B

Propene is reacted first with hydrogen chloride to produce X which is then reacted with aqueous sodium hydroxide to give Y. Finally, Y is reacted with excess acidified potassium dichromate solution.

$$\text{C}{\text{H}}_{\text{3}}\text{CHC}{\text{H}}_{\text{2}}\stackrel{\text{HCL}}{\to }\text{X}\stackrel{\text{NaOH(aq)}}{\to }\text{Y}\stackrel{{\text{H}}^{+}/\text{C}{\text{r}}_2{{\text{O}}_7}^{2-}\text{(aq)}}{\to }\text{Z}$$

What is the major product, Z? 

A.     CH₃CH(OH)CH₃

B.     CH₃COCH₃

C.     CH₃CH₂CHO

D.     CH₃(CH₂)₂COOH

B

Which statement is correct about configurational isomers?

A.  Configurational isomers can only be interconverted by breaking and reforming bonds.

B.  Configurational isomers have different molecular formulas but the same structural formulas.

C.  Configurational isomers are not distinct compounds.

D.  Configurational isomers always have identical physical properties.

A

Which is the correct combination of substitution reaction mechanisms?

A

Which product is formed when CH₃COCH₂CH₃ is reduced with sodium borohydride?

A.  CH₃CH₂CH₂CHO

B.  CH₃CH₂CH₂CH₂OH

C.  CH₃CH(OH)CH₂CH₃

D.  CH₃CH₂CH₂COOH

C

What is the major product of the reaction of HBr with but-1-ene?

A.   1-bromobutane

B.   2-bromobutane

C.   1,2-dibromobutane

D.   2,2-dibromobutane

B

Which statement about the reaction of a hydroxide ion with the organic reagent is correct?

A.   1-bromopentane predominantly follows an S_N1 mechanism.

B.   2-bromo-2-methylbutane predominantly follows an S_N2 mechanism.

C.   Reaction with 1-bromopentane occurs at a slower rate than with 1-chloropentane.

D.   Reaction with 1-bromopentane occurs at a slower rate than with 2-bromo-2-methylbutane.

D

What is the product of the reaction of propanal with lithium aluminium hydride, LiAlH₄?

A.  Propanoic acid

B.  Propanone

C.  Propan-1-ol

D.  Propan-2-ol

C

69% of the candidates identified the product of the reaction of propanal with LiAlH₄. The question had strong correlation with high-scoring candidates.

Which attacking species is matched with its mechanism of reaction?

D

What are the E/Z designations of these stereoisomers?

A

Mediocre performance with a good number of students who showed a lack of understanding of the E/Z designation for the alkene isomers.

Which is a major product of the electrophilic addition of hydrogen chloride to propene?

A. ClCH₂CH=CH₂

B. CH₃CH(Cl)CH₃

C. CH₃CH₂CH₂Cl

D. CH₃CH=CHCl

B

Markovnikov addition was handled much better by higher scoring candidates.

Which class of compound is formed when a ketone is reduced?

A. primary alcohol

B. secondary alcohol

C. ether

D. carboxylic acid

B

85 % of the candidates identified the secondary alcohol as the product of the reduction of a ketone. The other three distractors (primary alcohol, ether and carboxylic acid) were chosen almost equally by the remaining candidates.

Which compound exists as two configurational isomers?

A. CBr₂=CH₂

B. CH₂=CHBr

C. CHBr₂CH₂Br

D. CHBr=CHBr

D

71 % of the candidates identified 1,2-dibromoethene as having two configurational isomers. The most commonly chosen distractor was C which was the only saturated halogenoalkane, indicating that these candidates may have confused the term with “conformational” isomers.

Which can show optical activity?

A.  CHBrCHCl

B.  CH₃CH₂CHBrCH₂CH₃

C.  (CH₃)₂CBrCl

D.  CH₃CH₂CH(CH₃)Br

D

Which pair of isomers always shows optical activity?

A.     Cis-trans

B.     Enantiomers

C.     Conformational

D.     E/Z

B

Which can be reduced to an aldehyde?

A. Butanone

B. Butan-1-ol

C. Butanoic acid

D. Butan-2-ol

C

Which isomers exist as non-superimposable mirror images?

A.     cis-trans isomers

B.     diastereomers

C.     enantiomers

D.     structural isomers

C

What is name of this compound applying IUPAC rules?

A.     E 1-bromo-1-chlorobut-1-ene

B.     Z 1-bromo-1-chlorobut-1-ene

C.     E 1-bromo-1-chloro-2-ethylethene

D.     Z 1-bromo-1-chloro-2-ethylethene

B

Propene reacts separately with H₂O/H⁺ and H₂/Ni to give products X and Z respectively. 

What are the major products of the reactions?

A

What is the product of the reaction between pentan-2-one and sodium borohydride, NaBH₄?

A. Pentan-1-ol

B. Pentan-2-ol

C. Pentanoic acid

D. Pentanal

B

Which is the electrophile in the nitration of benzene?

A.  ${\mathrm{HNO}}_3$

B.  ${{\mathrm{NO}}_2}^{+}$

C.  ${{\mathrm{NO}}_2}^{-}$

D.  ${{\mathrm{NH}}_4}^{+}$

B

The vast majority selected the nitronium ion as the electrophile in the nitration of benzene.

What is molecule Z that is formed in step 1 of this synthetic route?

B

Higher scoring candidates did better at identifying the molecule that is formed in the synthesis of aminobenzene from nitrobenzene.

What is the product of the reduction of 2-methylbutanal?

A.     2-methylbutan-1-ol

B.     2-methylbutan-2-ol

C.     3-methylbutan-2-one

D.     2-methylbutanoic acid

A

Which solvent is aprotic?

A. H₂O

B. C₆H₅CH₃

C. CH₃OH

D. CH₃NH₂

B

Identifying protic from aprotic solvents was poorly done my most candidates.

What is the number of optical isomers of isoleucine?

A. 0

B. 2

C. 4

D. 8

C

How many chiral centres are there in the following molecule?

A.  2

B.  3

C.  4

D.  6

C

Which sequence of reagents converts propene to propanone?

A

66% of the candidates were able to identify the reagents needed to convert propene to propanone in three steps. This question discriminated well between high-scoring and low-scoring candidates.

Which compound can exist as cis- and trans-isomers?

C

Cis and trans isomerism on cyclic alkanes was poorly answered. This had the lowest discriminatory index on the test and all incorrect answers were fairly evenly distributed.

In which compound is the halogen substituted the most rapidly by aqueous hydroxide ions?

A. (CH₃)₃CCl

B. (CH₃)₃CI

C. CH₃CH₂CH₂CH₂Cl

D. CH₃CH₂CH₂CH₂I

B

How many chiral carbon atoms are present in one molecule of (CH₃)₂CHCHClCHBrCH₃?

A.   0

B.   1

C.   2

D.   3

C

Which statement is not correct regarding benzene?

A. It is planar.

B. The ring contains delocalized electrons.

C. It always reacts in the same way as alkenes.

D. The carbon–carbon bond has a bond order of 1.5.

C

73 % of candidates knew that benzene did not react the same way as alkenes.

What are the type of reaction and role of the nitronium ion, NO₂⁺, in the following reaction?

C₆H₆ + NO₂⁺ → C₆H₅NO₂ + H⁺

A

Good performance on a discriminating question in the type of reaction and role of the nitronium ion, NO₂⁺, in the nitration of benzene.