AS Level · Chemistry 9701 · Organic chemistry

Introduction to organic chemistry: AS Level Chemistry questions with answers

Free Introduction to organic chemistry questions for AS Level Chemistry (9701), part of Organic chemistry. Each question has the answer and the marking points an examiner would look for.

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Introduction to organic chemistry practice questions

Question 1Multiple choice · 1 markA* challenge

How many isomers are there of C3H6Cl2 (structural isomers only)?

  1. A 2
  2. B 3
  3. C 4
  4. D 5
Show answer

Answer: C

Question 2Multiple choice · 1 mark

Which term is described by this statement?
“Same structural formula, different spatial arrangement.”

  1. A structural isomers
  2. B mole
  3. C stereoisomers
  4. D disproportionation
Show answer

Answer: C

Question 3Multiple choice · 1 markA* challenge

How many isomers are there of C4H8 (including cis/trans isomers, alkenes only)?

  1. A 2
  2. B 3
  3. C 4
  4. D 5
Show answer

Answer: C

Question 4Multiple choice · 1 markA* challenge

How many chiral centres are there in a molecule of CH3CH2CH(CH3)CH2CH3?

  1. A 0
  2. B 1
  3. C 2
  4. D 3
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Answer: A

Question 5Structured · 4 marks

But-2-ene shows stereoisomerism.

(a)

Explain why but-2-ene has geometrical isomers.

[2]
(b)

Explain why butan-2-ol has optical isomers.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)restricted rotation; two different groups on each C
restricted rotation about C=C B1
each carbon of C=C has two different groups B1
2
(b)chiral carbon
a carbon atom attached to four different groups (chiral centre) B2
2
Question 6Structured · 12 marksA* challenge

Propene can be converted into several products.
reaction 1: propene + HBr → compound A (major product)
reaction 2: A + NaOH(aq), heat → compound B
reaction 3: B + acidified K2Cr2O7, heat → compound C
reaction 4: C + 2,4-DNPH → orange precipitate; C does not react with Tollens’ reagent.

(a)

Name compounds A, B and C.

[3]
(b)

Describe the mechanism of reaction 1, including the intermediate, and explain why A is the major product.

[5]
(c)

Name the type of reaction in reaction 2 and state why reaction 3 does not go further.

[2]
(d)

Give the structural formula of the organic product formed when C reacts with alkaline aqueous iodine, and state the observation.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)A 2-bromopropane; B propan-2-ol; C propanone
2-bromopropane B1
propan-2-ol B1
propanone B1
3
(b)electrophilic addition; curly arrow from C=C to H of HBr, H–Br heterolysis; secondary carbocation; Br− attacks; secondary carbocation more stable (more electron-donating alkyl groups)
curly arrow from π bond to H M1
H–Br bond breaking to Br M1
secondary carbocation drawn A1
Br− attacks carbocation M1
secondary carbocation more stable (inductive effect) B1
5
(c)nucleophilic substitution; ketone (secondary alcohol product) is not oxidised further
nucleophilic substitution B1
ketone cannot be oxidised (no H on carbonyl carbon) B1
2
(d)CHI3 (and CH3COO−); yellow precipitate
CHI3 B1
yellow precipitate B1
2

More Organic chemistry questions

HydrocarbonsHalogen compoundsHydroxy compoundsCarbonyl compoundsCarboxylic acids & derivativesNitrogen compoundsPolymerisationOrganic synthesisAnalytical techniques

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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in