A LevelChemistryOCRExam Questions4. Core Organic ChemistryBasic Concepts

Basic Concepts (OCR A Level Chemistry A): Exam Questions

Exam code: H432

3 hours40 questions

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Basic Concepts

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1
1 mark

What is the systematic name of the compound below?

Chemical structure showing CH3CHClC(CH3)ClCH3

  • 1,2-dichloro-1,2-dimethylpropane

  • 2,3-dichloro-2,3-dimethylpropane

  • 2,3-dichloro-2-methylbutane

  • 2,3-dichloro-3-methylbutane

Choose your answer

2
1 mark

The skeletal formulae of four alcohols, E, F, G and H, are shown below.

Four chemical structures labelled E to H, showing different alcohols with varying chain lengths and positions of hydroxyl groups.

Which pair of alcohols are structural isomers of each other?

  • E and F

  • E and G

  • E and H

  • F and G

Choose your answer

3
1 mark

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

  • Structural:

    CH2FCH2C(CH3)CH3

  • Displayed:

    Chemical structure showing a molecule with a carbon chain: H2C=CHCH2CH2CH2F, hydrogen atoms attached, and one fluorine atom at end.

  • Empirical:

    C5H9F

  • Skeletal:

    Chemical structure showing a branched carbon chain with a fluorine atom attached to the second carbon.

Choose your answer

4
1 mark

Which statement describes structural isomers?

  • Compounds with a different molecular formula and the atoms are arranged differently in space

  • Compounds with the same structural formula but the atoms are arranged differently in space

  • Compounds with the same empirical formula but different structural formulae

  • Compounds with the same molecular formula but different structural formulae

Choose your answer

5
1 mark

Which hydrocarbon does not belong to the same homologous series as the other three?

  • C8H18

  • C9H18

  • C11H24

  • C14H30

Choose your answer

6
1 mark

What is the identity of the functional group that is ringed in the molecule shown below?

Chemical structure of phenylacetone, showing a benzene ring connected to a two-carbon chain with a ketone group, highlighted with a dashed circle.

  • Aldehyde

  • Ketone

  • Carboxylic acid

  • Alkene

Choose your answer

7
1 mark

What is the systematic name of the compound below?

Chemical structure diagram showing CH3CHClCH(CH3)CH2CH3.

  • 2-chloro-3-methylpentane

  • 3-methyl-4-chloropentane

  • 2-ethyl-3-chlorobutane

  • 2-chloro-3-ethylbutane

Choose your answer

8
1 mark

The equation for an organic reaction is shown below.

Chemical reaction showing alcohol dehydration to form an alkene, using an acid catalyst. Reactants: Propanol; Products: Propene and water (H₂O).

What type of reaction is this?

  • Addition

  • Hydrolysis

  • Substitution

  • Elimination

Choose your answer

9
1 mark

Which equation shows homolytic fission?

  • H3C+ + Cl– → H3C–Cl

  • H3C–Br → H3C+ + Br–

  • H3C–CH3 → H3C• + •CH3

  • Cl• + •CH3  → H3C–Cl

Choose your answer

10
1 mark

How many structural isomers have the molecular formula C6H14?

  • 3

  • 4

  • 5

  • 6

Choose your answer

1
1 mark

What is the systematic name of the compound below?

Skeletal formula showing a three carbon chain with an OH group on carbon-1, a methyl group on carbon -2 and carbon-3 as a carbonyl group

  • 1-carbonyl-2-methylpropan-3-ol

  • 2-methoxypropan-1-ol

  • 2-methyl-3-hydroxypropanone

  • 3-hydroxy-2-methylpropanal

Choose your answer

2
1 mark

The skeletal formula of an organic compound is shown below.

Skeletal chemical structure CH3COC(CH3)2CHOHCH3

What is the molecular formula of the organic compound?

  • C7H12O2 

  • C7H13O2 

  • C7H14O2 

  • C7H15O2 

Choose your answer

3
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1 mark

What is the general formula for the homologous series of ketones?

  • C3H6O

  • CnH2n-1O

  • CnH2nO

  • CnH2n+1O

Choose your answer

4
1 mark

How can the molecule below be described?

Chemical structure of 2-methylcyclohexa-1-3-diene

  • Aromatic and alicyclic

  • Aliphatic and saturated

  • Alicyclic and saturated

  • Alicyclic and unsaturated

Choose your answer

5
1 mark

Which compound(s) is a / are structural isomer(s) of C6H12O?

  1. Cyclohexanol

  2. Hexan-3-one

  3. 2,3-dimethylbut-3-en-2-ol

  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

Choose your answer

6
1 mark

How many structural isomers of C4H10O are alcohols?

  • 2

  • 3

  • 4

  • 5

Choose your answer

7
1 mark

Which statement(s) is / are correct for the organic compound below?

Skeletal formula of pent-2-ene

  1. The systematic name is pent-3-ene.

  2. The empirical formula is CH2.

  3. It is a structural isomer of cyclopentane.

  • 1, 2 and 3

  • Only 1 and 2

  • Only 1 and 3

  • Only 2 and 3

Choose your answer

8
1 mark

Which statement(s) is / are correct about bond fission?

  1. Each bonding atom receives one electron from the bonding pair in heterolytic fission.

  2. Radicals are formed during homolytic fission.

  3. Heterolytic fission forms anions and cations.

  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

Choose your answer

9
1 mark

Which diagram shows the heterolytic fission of the C-Cl bond to form a carbocation and Cl–?

  • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-cl
  • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-cl-
  • ocr-as-4-1m-mcq-q9-heterolytic-fission-of-chloropropane-2--ve-ions
  • ocr-as-4-1m-mcq-q9-homolytic-fission-of-chloropropane

Choose your answer

10
1 mark

Which statement(s) is / are correct about the members of a homologous series?

  1. All members have the same general formula.

  2. The members have similar chemical properties.

  3. The members show a gradual change in physical properties.

  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

Choose your answer

1
1 mark

What is the systematic name of the compound below?

Chemical structure of CH3CH2C(CH3)C(CH3)CH(CH3)CH2CH3

  • 3,4,5-trimethylhept-3-ene

  • 3,4,5-trimethylhept-4-ene

  • 4-ethyl-1,2,3-trimethylpent-2-ene

  • 5-ethyl-3,4-dimethylhex-3-ene

Choose your answer

2
1 mark

Which row is correct?

 

IUPAC name

General formula

Skeletal formula

Structural formula

A

2-methylpropanal

CnH2n+1O

2-methylpropanal

CH3CH(CH3)CHO

B

4-methylpentylamine

CnH2n+1NH2

 

4-methylpentylamine

CH3CH2CH2CH(CH3)CH2NH2

C

4-methylhexan-2-one

CnH2nO

4-methylhexan-2-one

CH3CH2CH(CH3)CH2COCH3

D

ethyl propanoate

CnH2nO2

 

ethyl-propanoate

CH3COOCH2CH2CH3

    Choose your answer

    3
    1 mark

    How many structural isomers of C5H13N are primary amines?

    • 7

    • 8

    • 9

    • 10

    Choose your answer

    4
    1 mark

    Which pair of compounds are structural isomers of each other?

    • E-but-2-ene and Z-but-2-ene

    • Propanone and propan-2-ol

    • 2-methyl-3-ethylbutane and 2,3-dimethylpentane

    • Butanoic acid and methyl propanoate

    Choose your answer

    5
    1 mark

    Which equation is correct?

    ocr-as-4-1h-mcq-q5-curly-arrows

      Choose your answer