A Level Chemistry (A2) chapter 7: An introduction to A Level organic chemistry MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

96 exam-style questions on An introduction to A Level organic chemistry, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

96 questions · 4 topics · 10 per test

Test this chapter freeAll A Level Chemistry (A2) chapters

What chapter 7 covers

Ten An introduction to A Level organic chemistry questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. Which statement describes the intermediate formed when an electrophile E+ attacks a benzene ring?

  1. A
    it is a neutral molecule in which E has added across one C=C bond of the ring
  2. B
    it is a positive ion in which one ring carbon is sp3 and bonded to both H and E, and the delocalised system is partly broken
  3. C
    it is a negative ion in which the ring carries the electron pair from E
  4. D
    it is a positive ion with a complete six-electron delocalised ring and E attached by a π bond
Show answer

Answer: B. The ring’s π electrons form a bond to E+, so the intermediate carries the positive charge. The attacked carbon becomes sp3, leaving four π electrons over five carbons until H+ is lost.

2. Which pair of compounds would be expected to have the most similar chemical reactions?

  1. A
    phenol and phenylmethanol
  2. B
    phenol and 4-methylphenol
  3. C
    ethanol and ethanal
  4. D
    benzoic acid and methyl benzoate
Show answer

Answer: B. Phenol and 4-methylphenol both have an –OH joined directly to a benzene ring, so both are phenols (both react with NaOH(aq) and with bromine water). Phenylmethanol, C6H5CH2OH, has its –OH on a side-chain carbon, so it behaves as an alcohol.

3. Why can two enantiomers of a drug have different effects in the body?

  1. A
    the two enantiomers have different molecular formulae
  2. B
    one enantiomer is always more soluble in blood plasma
  3. C
    drug receptors and enzymes are themselves chiral, so only one enantiomer fits the binding site correctly
  4. D
    the body converts one enantiomer into a different structural isomer
Show answer

Answer: C. The binding sites are built from chiral amino acids. Like a left hand in a right glove, the mirror-image molecule cannot make the same contacts, even though its other properties are identical.

4. Which statement about the carbon–carbon bonds in benzene is correct?

  1. A
    all six are the same length, between that of a C–C single bond and a C=C double bond
  2. B
    they are alternately long and short, as in a single and double bond pattern
  3. C
    all six are the same length as the C=C bond in ethene
  4. D
    all six are the same length as the C–C bond in ethane
Show answer

Answer: A. The π electrons are delocalised evenly round the ring, so every C–C bond is identical, with a length (about 0.139 nm) between the single bond (0.154 nm) and double bond (0.134 nm) values.

5. Which statement about the shape of a methylbenzene molecule, C6H5CH3, is correct?

  1. A
    all fifteen atoms lie in one plane
  2. B
    only the six ring carbons lie in one plane; the ring hydrogens point above and below it
  3. C
    the ring is puckered like cyclohexane because of the methyl group
  4. D
    the six ring carbons, the five ring hydrogens and the methyl carbon lie in one plane
Show answer

Answer: D. The sp2 ring carbons and every atom bonded directly to them lie in the plane of the ring. The methyl carbon is sp3, so its three hydrogens are arranged tetrahedrally and cannot all lie in that plane.

6. Which compound has two chiral centres in each molecule?

  1. A
    CH3CH(OH)CH2CH3
  2. B
    CH3CH(Cl)CH(CH3)2
  3. C
    HOCH2CH(OH)CH2OH
  4. D
    CH3CH(OH)CH(Cl)CH3
Show answer

Answer: D. In CH3CH(OH)CH(Cl)CH3 both C2 and C3 carry four different groups. In CH3CH(Cl)CH(CH3)2 the carbon with two methyl groups is not chiral, and the central carbon of HOCH2CH(OH)CH2OH carries two identical CH2OH groups.

7. How many σ bonds are there in one molecule of phenol, C6H5OH?

  1. A
    11
  2. B
    12
  3. C
    13
  4. D
    14
Show answer

Answer: C. Six ring C–C σ bonds, five C–H, one C–O and one O–H give 13. The π electrons of the ring are additional and are not counted as σ bonds.

8. Which reaction of methylbenzene is an electrophilic substitution?

  1. A
    with Cl2 in ultraviolet light
  2. B
    with hot alkaline KMnO4, then dilute acid
  3. C
    with H2 and a nickel catalyst, heated
  4. D
    with CH3COCl and AlCl3, heated
Show answer

Answer: D. Friedel–Crafts acylation replaces a ring H by CH3CO– through an electrophile formed with AlCl3. Chlorine in UV light substitutes in the side chain by a free-radical mechanism; KMnO4 oxidises and H2/Ni adds.

9. Typical lengths: C–C 0.154 nm, C=C 0.134 nm, C≡C 0.120 nm. What is the best estimate of every carbon–carbon bond length in benzene?

  1. A
    0.120 nm
  2. B
    0.134 nm
  3. C
    0.139 nm
  4. D
    0.154 nm
Show answer

Answer: C. The delocalised π system spreads the bonding evenly, so all six bonds are identical and intermediate between single and double, at about 0.139 nm.

10. If benzene really had three fixed C=C and three C–C bonds alternating around the ring, how many different 1,2-dibromobenzenes would exist? (In practice only one is known.)

  1. A
    1
  2. B
    2
  3. C
    3
  4. D
    6
Show answer

Answer: B. The two Br atoms could be on carbons joined by a C=C or by a C–C bond, giving two isomers. Only one exists because all six bonds are identical, which supports delocalisation.

Start the chapter testAbout the A Level Chemistry (A2) test

Read the notes for this chapter

Ways to practise this chapter

An introduction to A Level organic chemistry: questions students ask

How many An introduction to A Level organic chemistry MCQs are there?

96, each with the answer and a short explanation, across 4 topics: Formulas, functional groups and the naming of organic compounds, Characteristic organic reactions, Shapes of aromatic organic molecules; σ and π bonds, Isomerism: optical. Every chapter test draws ten of them, so you can take it many times.

Is the A Level Chemistry (A2) chapter 7 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Keep going

← Chapter 6: Chemistry of transition elementsChapter 8: Hydrocarbons →All chaptersStuck? Ask a question