OCR A Level Chemistry A Synthesis and analytical techniques June 2018 question paper H432/02

Which compound is used as a standard for NMR chemical shift measurements?

A Si(CH₃)₄

B CDCl₃

C D₂O

D CCl₄

Which compound is a secondary amide?

Which compound does not react with nucleophiles?

A CH₃CH₂CHO

B CH₃CHCH₂

C CH₃CH₂COCH₃

D CH₃CH₂CH₂Cl

Which structure represents an alicyclic compound?

Which molecule is not planar?

A C₂H₄

B C₂H₆

C H₂CO

D HCN

What is the number of peaks in the¹H NMR spectrum of HOOCCH₂CHOHCH₂COOH?

A 3

B 4

C 5

D 6

Ethanol can be prepared by different reactions.

Which reaction has the lowest atom economy?

A C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

B C₂H₄ + H₂O → C₂H₅OH

C C₂H₅Br + H₂O → C₂H₅OH + HBr

D CH₃COOC₂H₅ + H₂O → C₂H₅OH + CH₃COOH

The breakdown of ozone is catalysed by NO radicals.

Which equation is a propagation step in the mechanism for this process?

A NO + O₂ → N + O₃

B NO + O₂ → NO₂ + O

C N + O₃ → NO + O₂

D NO₂ + O → NO + O₂

Benzene reacts with an organic reagent in the presence of a halogen carrier to form phenylethanone.

Which organic reagent is required?

A CH₃CH₂OH

B CH₃CHO

C CH₃COCl

D CH₃COOH

How many straight-chain structural isomers of C₇H₁₅Cl contain a chiral carbon atom?

A 1

B 2

C 3

D 4

The mass spectrum of (CH₃)₂CHCH₂OH is shown below.

Which ion is responsible for the peak with the greatest relative intensity?

A CHCH₂OH⁺

B CH₃CH₂CH⁺

C (CH₃)₂CH⁺

D CH₃CO⁺

Which statement(s) support(s) the delocalised model for the structure of benzene?

1 All carbon–carbon bonds have the same length.

2 The enthalpy change of hydrogenation of benzene is less exothermic than expected.

3 Bromine reacts with benzene less readily than with cyclohexene.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

A solid organic compound can be purified by recrystallisation.

Which statement(s) about recrystallisation is/are true?

1 The organic compound is more soluble in hot solvent.

2 The hot solution is cooled before the purified organic compound is collected.

3 The melting point of the purified organic compound is lower than the impure compound.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Which of the following could react with the compound below to form a carbon–carbon bond?

2 KCN in ethanol

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

This question is about reactions of organic compounds containing carbon, hydrogen and oxygen.

A chemist investigates two reactions of alcohol A, shown below.

What is the systematic name of alcohol A ?

What is the structural formula of alcohol A ?

The chemist heats alcohol A with an acid catalyst to form a mixture containing alkenes.

Draw the structures of the two alkenes formed in this reaction.

The chemist heats alcohol A with sodium chloride and sulfuric acid.

Construct a balanced equation for this reaction. Show structures for the organic compounds in your equation.

The general formula of an -amino acid is RCH(NH₂)COOH.

The -amino acid cysteine (R = CH₂SH) shows optical isomerism.

Draw 3-D diagrams to show the optical isomers of cysteine.

The -amino acid lysine (R = (CH₂)₄NH₂) reacts with an excess of dilute hydrochloric acid to form a salt.

Draw the structure of the salt formed in this reaction.

-Amino acids can react to form proteins.

A short section of a protein chain is shown below.

A student hydrolyses the protein with hot NaOH(aq).

Draw the structures of the organic products formed from this section of the protein.

This question is about aromatic compounds.

Phenol undergoes nitration more readily than benzene.

A student carries out the nitration of phenol with dilute nitric acid to produce 2-nitrophenol and 4-nitrophenol.

A small amount of 3-nitrophenol is also produced.

2-nitrophenol 3-nitrophenol 4-nitrophenol

The student thought that¹³C NMR spectroscopy could be used to distinguish between these three nitrophenols.

Explain whether the student is correct.

Explain why phenol is nitrated more readily than benzene.

Methylbenzene reacts with sulfur trioxide, SO₃, to form D, shown below.

The electrophile in this reaction is SO₃.

Complete the mechanism for the formation of D. Show curly arrows and the structure of the intermediate.

This question is about the hydrolysis of haloalkanes.

The rate of hydrolysis of a haloalkane depends on the halogen present.

State and explain how the halogen in the haloalkane affects the rate of hydrolysis.

A student hydrolyses a haloalkane, E, using the following method.

• 0.0100 mol of haloalkane E is refluxed with excess NaOH(aq) to form a reaction mixture containing an organic product F.

• The reaction mixture is neutralised with dilute nitric acid.

• Excess AgNO₃(aq) is added to the reaction mixture. 1.88 g of a precipitate G forms.

Organic product, F, has a molar mass of 74.0 g mol⁻¹ and has a chiral carbon atom.

Draw a labelled diagram to show how the student would carry out the hydrolysis of haloalkane E.

Analyse the information to identify E, F and G.

Show your working.

Cinnamaldehyde and methylcinnamaldehyde are naturally occurring organic compounds.

Methylcinnamaldehyde is an E stereoisomer.

Explain this statement in terms of the Cahn-Ingold-Prelog (CIP) rules.

A student plans to carry out some chemical tests on both cinnamaldehyde and methylcinnamaldehyde.

Suggest a suitable chemical test to confirm that both compounds contain an unsaturated carbon chain.

Your answer should include the reagent and observations.

Describe a chemical test to confirm that both compounds contain an aldehyde functional group.

Your answer should include the reagent and observations.

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.

This question is about aromatic carboxylic acids and their derivatives.

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

The relative molecular masses and boiling points of some fuels are shown in Table 22.1.

Write an equation for the incomplete combustion of heptane.

Explain the difference in the boiling points of the fuels in Table 22.1.

Fuel additives are often used to improve the combustion of a fuel.

Compound N is a fuel additive containing carbon, hydrogen and oxygen only.

Complete combustion of 1.71 g of compound N produces 2.97 g of CO₂ and 1.62 g of H₂O. The relative molecular mass of compound N is 76.0.

Calculate the molecular formula of N and suggest a possible structure for the compound.

compound N

Solketal has been investigated as a potential fuel additive.

Solketal is synthesised from propane-1,2,3-triol and a carbonyl compound.

Construct a balanced equation for this synthesis. Show structures for the organic compounds in your equation.

* A scientist is researching compounds that might be suitable as fuel additives. One of the compounds gives the analytical results below.

Elemental analysis by mass: C: 54.54%; H: 9.10%; O: 36.36%

Mass spectrum: Molecular ion peak at m / z = 132.0

¹H NMR spectrum in D₂O

The numbers by the peaks are the relative peak areas.

When the spectrum is run without D₂O, there are two additional peaks with the same relative peak areas at 11.0 ppm and 3.6 ppm.

Use the information provided to suggest a structure for the compound.

Show all your reasoning.