CAIE IGCSE Chemistry 11.5 Alkenes Questions

Practise alkene reactions and tests by using C=C bonding, cracking equations, bromine water and addition-product reasoning.

Syllabus
2026–2028
Course
Chemistry 0620

Exam points

  • use C=C and bromine water decolourisation to recognise unsaturated compounds
  • complete cracking equations that form alkenes, hydrogen or smaller alkanes
  • explain addition reactions from a single product and a reacting carbon-carbon double bond

Question 1

[Maximum number: 1]

38 P, Q, R and S are four organic compounds.
P is an unsaturated hydrocarbon.
Q burns but otherwise is unreactive.
R contains a C-C single bond and a C=C double bond.
S undergoes addition polymerisation.
Which compounds are alkenes?

A

P and R only

B

P, R and S

C

P, Q and S

D

Q, R and S

Question 2

[Maximum number: 1]

Which compound rapidly decolourises aqueous bromine?

A

propane

B

propanoic acid

C

propanol

D

propene

Question 3

[Maximum number: 1]

Alkenes react with steam in an addition reaction.

Some alkenes produce only one alcohol product.
Some alkenes produce two different alcohols which are structural isomers.
Which row gives the number of alcohol isomers formed when ethene reacts with steam and when propene reacts with steam?

ethene + steam

propene + steam

1

1

1

2

2

1

2

2

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