Question
These reactions are favoured when they occur at a sterically hindered carbon centre. For 10 points each:
[10m] Name this reaction mechanism, in which a leaving group is replaced [emphasise] after the formation of a carbocation intermediate, giving a rate law that is considered independent of the concentration of the incoming species.
ANSWER: SN1 [or unimolecular nucleophilic substitution; accept nucleophilic substitution 1; prompt on partial answer, do not accept or prompt on SN2 or bimolecular etc.]
[10h] Because they stabilise both the charged intermediate and the leaving group, speeding up the reaction, solvents for SN1 reactions are commonly chosen to have these [emphasise] two properties.
ANSWER: polar and protic [do not accept or prompt partial answers]
[10e] Common reactants in SN1 reactions include secondary and tertiary haloalkanes, in which an alkane has a hydrogen substituted by an element from group 7. Because its anion is a good leaving group, this element, below chlorine and above iodine in the periodic table, is a common choice.
ANSWER: bromine [or Br; accept bromide or Br- (“B R minus”)]
Summary
| 2023 UMN COOT | 08/19/2023 | Y | 3 | 13.33 | 100% | 33% | 0% |
Data
| Palestrina Sawayama | BHSU | 10 | 0 | 10 | 20 |
| doubleplusnegfive | Our Job is Buzz | 0 | 0 | 10 | 10 |
| Weird Klaus Barbie | Jeff Weiner Fan Club | 0 | 0 | 10 | 10 |