alkenes PMT Flashcards
Q1b Explain why there is an attraction between a C=C double bond and Br2
C = C is a high electron density area
Br - Br becomes polarised. Delta + Br attracted to C = C
Q4b State what you would observe if bromine water was added to poly(chloroethene). Explain this observation.
observation - no reaction
explanation - polymer is saturated
Q10c Explain why the two products are formed in different amounts.
The major product is formed via a tertiary carbocation and the minor product is formed via a secondary carbocation
The tertiary is more stable than the secondary
Q11 MCQ
Consider the reaction between propene and hydrogen bromide to form the major product.
Which species is formed in the mechanism of this reaction?
A CH3–C+H–CH2Br
B CH3–CHBr–C+H2
C CH3–C+H–CH3
D CH3–CH2–C+H2
C
Q12 MCQ
Which statement about E-1,2-dichloroethene is correct?
A It has the same boiling point as Z-1,2-dichloroethene.
B It forms a polymer with the same repeating unit as Z-1,2-dichloroethene.
C It has the same IR spectrum as Z-1,2-dichloroethene
in the range 400–1500 cm−1.
D It has a molecular ion peak different from that of
Z-1,2-dichloroethene in its mass spectrum.
B
Q13 MCQ
Which statement about ethene is correct?
A It has no geometric isomers because there is free rotation around the C=C bond.
B It reacts with HBr in a nucleophilic addition reaction.
C It burns in excess oxygen to produce carbon dioxide and water.
D The C=C bond is twice as strong as the C–C bond in ethane.
C
Q14 c Explain how three isomeric products are formed when HY reacts with but-1-ene.
The major product exists as a pair of enantiomers The third isomer is 1-bromobutane (minor product) Because it is obtained via primary carbocation
