Orgo Exam 3

Chapter 7

What is the rate-determining step of an E1 or SN1 reactions?

Formation of the carbocation

III, I, V, IV, II

Product A for reaction I, and a mixture of products A and B for reaction II. 

Match the Carbon-halogen bond strengths for methyl halides

H3C-F

H3C-Cl

H3C-Br

H3C-I

472 kJ/mol, 239 kJ/mol, 350 kJ/mol, 293 kJ/mol

H3C-F —> 472 kJ/mol

H3C-Cl —> 350 kJ/mol

H3C-Br —> 293 kJ/mol

H3C-I —> 239 kJ/mol

What dihedral angle does an anti-coplanar transition state refer to

180 degrees

Match the carbon-halogen bond lengths for the methyl halides

H3C-F

H3C-Cl

H3C-Br

H3C-I

1.39 Å, 214 Å, 1.78 Å, 1.93 Å 

H3C-F —> 1.39 Å

H3C-Cl —> 1.78 Å

H3C-Br —> 1.93 Å

H3C-I —> 2.14 Å

water

IV

Reaction rate is slowed by solvation of the anion

π

What does racemization refer to?

loss of optical activity

I-

Put in order of INCREASING polarizability (1 being the least polarizable and 4 being the most polarizable) 

H3C-F

H3C- I 

H3C-Cl

H3C-Br

1. H3C-F

2. H3C- Cl

3. H3C-Br

4. H3C-I

Both SN1 and E1

SN2

endergonic, shown by the blue line

hyperconjugation

Hammond-Leffler postulate

Which compound can undergo acid-mediated dehydration under the mildest conditions? 

F-

II, IV, V, I, III

Put in order of DECREASING polarizability (1 being the most polarizable and 4 being the least polarizable) 

H3C-F

H3C- I 

H3C-Cl

H3C-Br

1. H3C-I

2. H3C- Br 

3. H3C-Cl

4. H3C-F