Optical activity and reaction mechanisms

Question 1

a mechanism described as bimolecular haS

Answer 1

two species reacting in the rate-determining step, making it SN2

Question 2

a mechanism described as unimolecular has

Answer 2

one species reacting in the rate-determining step, making it SN1

Question 3

SN1 stands for

Answer 3

Substitution, Nucleophilic 1= unimolecular and first order

Question 4

SN2 stands for

Answer 4

Substitution, Nucleophilic 2= bimolecular and second order

Question 5

the mechanism for the reaction between the primary halogenoalkane bromoethane and hydroxide ions is an SN…..mechanism because

Answer 5

SN2

• this means two species react in the first step
• it also means we draw the second step inside square brackets with a - charge and dashed lines

Question 6

the mechanism for the reaction between the tertiary halogenoalkane bromofluoroethane and the hydroxide ions is an SN… mechanism because

Answer 6

• SN1

- there is only one species involved in the rate determining step

Question 7

the general rule for whether a halogenoalkane will react in an SN1 or SN2 mechanism is

Answer 7

primary= SN2
secondary= SN1 / SN2 (depends on conditions and the halogenoalkane)
tertiary= SN1