11.3 Alkenes, Set A To print: Ctrl + P, paper A4, margins Default.
Learners' AlleyDesigned by Khow Willard
11.3

Alkenes

Set AFoundations
Name
Time 1 hour
Total 29 marks

A Data Booklet may be used.

A

From the lesson

10 marks
1
CommonWhich shows cis–trans isomerism: (a) but-1-ene, (b) pent-2-ene, (c) 2-methylbut-2-ene?
[1]

Source: Learners' Alley, Alkenes slides

2
CommonGive the major product of but-1-ene with HBr, and explain why it is major.
[3]

Source: Learners' Alley, Alkenes slides

3
An alkene, C5H10, gives propanone and ethanoic acid with hot acidified KMnO4. Deduce its structure.
[2]

Source: Learners' Alley, Alkenes slides

4
Why can but-2-ene show cis–trans isomerism?
[1]

Source: Learners' Alley, Alkenes slides

5
Reagents and conditions to make propan-2-ol from propene?
[1]

Source: Learners' Alley, Alkenes slides

6
Name the mechanism of propene + HBr.
[1]

Source: Learners' Alley, Alkenes slides

7
What does =CH2 give with hot acidified KMnO4?
[1]

Source: Learners' Alley, Alkenes slides

B

Practice

19 marks
8

CommonEthene reacts with bromine to form dibromoethane. Which statement best describes the organic intermediate in this reaction?

AThe shape about each carbon in the intermediate is trigonal planar.
BIt has a negative charge.
CIt is an electrophile.
DIt is a free radical.
Answer [1]

Source: SRJC 2009 Prelim P1 Q24, via EJC 2022 JC1 Alkenes Tutorial, Q5

9

Which of the following statements about the two alkenes CH3CH2CH=CH2 and CH3CH=CHCH3 is correct?

ANeither exhibits cis-trans isomerism.
BNeither reacts with bromine to give 1,4-dibromobutane.
CNeither reacts with hydrogen to form butane.
DNeither may be oxidised by alkaline potassium manganate(VII) to form a diol.
Answer [1]

Source: A Level 1990 P1 Q22, via EJC 2022 JC1 Alkenes Tutorial, Q12

10
Explain why alkenes are chemically more reactive than alkanes.
[2]

Source: EJC 2022 JC1 Alkenes Tutorial, Q1

11

CommonFor each pair of compounds, describe one simple chemical test which would enable you to distinguish between them. State clearly how each compound behaves in the test and write balanced equations for the reactions involved.

(a)
ethane and ethene
[2]
(b)
but-1-ene and but-2-ene
[3]

Source: RJC H2 Chemistry Tutorial 12 (Alkenes), Discussion Q3

12
Common2-chloropropane can be formed when propene, C3H6, is reacted with HCl gas: CH2=CHCH3 + HCl → CH3CHClCH3. Name and describe the mechanism for the reaction between propene and hydrogen chloride, showing curly arrows, charges, dipoles and any relevant lone pairs.
[3]

Source: 2019 CJC J1 Promo P2 Q6(d)

13

ChallengeSix isomeric hydrocarbons, A to F, have the same molecular formula, C4H8. A and B are geometrical isomers and A has a higher boiling point than B. C reacts with aqueous bromine to yield a product G, which has a chiral centre. D reacts with hydrogen to form a branched-chain alkane, H. E and F are saturated hydrocarbons.

(a)
Suggest a structural formula for each of the hydrocarbons A to F. Give the IUPAC name of each compound.
[3]
(b)
Explain why the boiling point of A is higher than that of B.
[2]
(c)
Give the structural formulae of the products obtained when each of the hydrocarbons A to D is treated with hot, alkaline potassium manganate(VII).
[2]

Source: RJC H2 Chemistry Tutorial 12 (Alkenes), Discussion Q5(i), (iii) and (iv)