Which monomer could create this polymer?

A.     But-2-ene

B.     But-1-ene

C.     Propene

D.     2-Methylprop-1-ene

A

Which reagents and conditions are best for converting propan-1-ol into propanoic acid?

A.  Reflux with acidified potassium dichromate (VI)

B.  Reflux with LiAlH₄

C.  Distil with acidified potassium dichromate (VI)

D.  Distil with LiAlH₄

A

The vast majority of students identified the best reagents and conditions for converting propan-1-ol into propanoic acid.

Which is the correct combination of substitution reaction mechanisms?

A

What is the IUPAC name of the following molecule?

A. 2-bromo-3-ethylbutane

B. 3-methyl-4-bromopentane

C. 2-ethyl-3-bromobutane

D. 2-bromo-3-methylpentane

D

Another relatively high scoring question on IUPAC nomenclature.

Which functional group is responsible for the pK_b of 4.1 in this compound?

A. Amido

B. Amino

C. Chloro

D. Ether

B

Which compound has the lowest boiling point?

A. CH₃CH₂CH₂CH₂CH₂CH₃

B. CH₃CH₂CH₂CH₂CH₃

C. CH₃CH(CH₃)CH₂CH₃

D. CH₃C(CH₃)₂CH₃

D

Surprisingly, this was one of the challenging questions on the paper. Only 63 % of the candidates chose dimethylpropane as the compound having the lowest boiling point. The most commonly chosen distractor was pentane (B) which did not take into account the effect of branching on the strength of London dispersion forces.

Methane reacts with chlorine in sunlight.

CH₄ (g) + Cl₂ (g) → CH₃Cl (g) + HCl (g)

Which type of reaction occurs?

A. free-radical substitution

B. electrophilic substitution

C. nucleophilic substitution

D. electrophilic addition

A

85 % of the candidates chose free-radical substitution as the type of reaction occurring between methane and chlorine in sunlight.

Which compound with the molecular formula ${\mathrm{C}}_4{\mathrm{H}}_8\mathrm{O}$ has this high resolution ${}_1\mathrm{H} \mathrm{NMR}$?

From: libretexts.org. Courtesy of Chris Schaller, Professor (Chemistry)
at College of Saint Benedict/Saint John’s University.

A.  but-3-en-2-ol, ${\mathrm{CH}}_2=\mathrm{CHCH}\left(\mathrm{OH}\right){\mathrm{CH}}_3$

B.  butanal, ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CHO}$

C.  butanone, ${\mathrm{CH}}_3{\mathrm{COCH}}_2{\mathrm{CH}}_3$

D.  but-3-en-1-ol, ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{CH}}_2\mathrm{OH}$

B

Just over 50% of candidates could identify the correct compound from high resolution 1H NMR data. The question had a relatively high discriminatory index.

Which compounds can be reduced?

I.     C₂H₄
II.     CH₃COOH
III.     CH₃CHO

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

D

Which alcohol would produce a carboxylic acid when heated with acidified potassium dichromate(VI)?

A. propan-2-ol

B. butan-1-ol

C. 2-methylpropan-2-ol

D. pentan-3-ol

B

75 % of candidates could correctly identify the oxidation of a primary alcohol to form carboxylic acid.

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

C

What is the major product of the reaction between 2-methylbut-2-ene and hydrogen bromide?

A.     3-bromo-2-methylbutane

B.     3-bromo-3-methylbutane

C.     2-bromo-3-methylbutane

D.     2-bromo-2-methylbutane

D

Which reaction involves homolytic fission?

A.  CH₄ + Cl₂

B.  CH₃Br + NaOH

C.  (CH₃)₃CBr + NaOH

D.  C₆H₆ + HNO₃ + H₂SO₄

A

A well answered question. 66% of the candidates identified the chlorination of methane as the reaction involving homolytic bond fission.

Which is a secondary alcohol?

B

Which would be the most effective method to distinguish between liquid propan-1-ol and propan-2-ol?

A.     Observation of colour change when warmed with acidified potassium dichromate

B.     Determination of m/z value of molecular ion in the mass spectrum

C.     Determination of percentage composition

D.     ¹H NMR spectroscopy

D

Which molecule can be oxidized to a carboxylic acid by acidified potassium dichromate(VI)?

A.  Propan-1-ol

B.  Propan-2-ol

C.  2-methylpropan-2-ol

D.  Propanone

A

Another well answered question with the vast majority understanding that only propan-1-ol can be oxidized to a carboxylic acid.

What must be present on a nucleophile?

A. Negative charge

B. Lone pair of electrons

C. Positive charge

D. Symmetrical distribution of electrons

B

72 % of the candidates chose B (a nucleophile must have a lone pair of electrons). The most commonly chosen distractor was A (a nucleophile must have a negative charge). Some teachers commented that both answers A and B are correct. However, the word “must” in the question means B is the only answer. Candidates are aware that some nucleophiles like water are neutral. Moreover, the definition of a nucleophile is clearly stated in the syllabus (topic 10.2).

Which can be reduced to a secondary alcohol?

A.  C₂H₅COOH

B.  CH₃CH₂OCH₃

C.  (CH₃)₂CHCHO

D.  CH₃COC₂H₅

D

What is the name of this compound using IUPAC rules?

A. 2,3-diethylbutane

B. 2-ethyl-3-methylpentane

C. 3-methyl-4-ethylpentane

D. 3,4-dimethylhexane

D

This was the easiest question on the paper. 97 % of the candidates recognized the correct IUPAC name of the compound.