2007-203%20midterm2KEY

2007-203%20midterm2KEY - Chemistry 203 Midterm 2-Nov. 13,...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Page 1 of 11 Chemistry 203 Midterm 2-Nov. 13, 2007 surname given names last initial student number signature MOLECULAR MODELS MAY BE USED 1 2 3 4 5 raw total total 23 10 11 24 12 80 10 1. (23 marks) Answer each of the following parts. a) Draw the major contributing resonance structures of anion A : C O N A C O N C O N b) Circle any compound that has only two signals in its 1 H NMR spectrum: O O O O all of these none of these c) Circle the alkyl bromide that would undergo reaction with sodium thiophenoxide (NaSPh) in a suitable solvent (under otherwise identical conditions) at the slowest rate. Br CH 3 Br Br Br Br H
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Student name/id number: ___________________________________________ Page 2 of 11 d) Consider the organic bromides 1 and 2 (below): Under otherwise identical conditions, the organic bromide that undergoes a S N 1 reaction at the slower rate is: 1 2 Br Br 1 2 (circle your answer) Justify your answer using brief comments (pictures=1000 words). 2° carbocation; positive charge localized in an empty p orbital alkenyl carbocation; positive charge localized in an empty sp 2 orbital -more s character; closer to nucleus; highly unfavorable to have positive charge there; this cation is too unstable to form readily (the activation energy to form this is too high) + e) Consider the following two reactions: Under otherwise identical conditions, the reaction that proceeds at the faster rate is: 1 2 N N ethyl bromide solvent ethyl bromide S N 2 product S N 2 product (1) (2) (circle your answer) ii) Justify your answer using brief comments (pictures=1000 words).
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/09/2009 for the course CHEM 203 taught by Professor Unknown during the Spring '98 term at UBC.

Page1 / 10

2007-203%20midterm2KEY - Chemistry 203 Midterm 2-Nov. 13,...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online