Video Solution: Choose the more stable alkene in each of the following pairs...

Sign up for free to keep watching this solution

Choose the more stable alkene in each of the following pairs. Explain your reasoning. 

Answer the following questions regarding cyclopropane and propane.

a. Provide an approximate pKa value for the C-H bond of propane.

b. Using pictures and a minimum amount of words, name and describe the types of strain associated with cyclopropane.

c. The Csp3 orbitals are able to relieve some of the strain by adjusting slightly. Draw a molecular orbital representation of cyclopropane.

d. Please provide a name for the type of “adjusted” bonds you drew in part c.

e. Due to the reorganization of the hybrid orbitals in cyclopropane, the s character of the carbon-hydrogen bonds actually increases. Do you think this will increase or decrease the pKa value of a C-H bond in cyclopropane? Why or why not?

Watch Solution

Draw all cycloalkanes that correspond to molecular formula C5H10, and circle the least strained of them.

Watch Solution

For the pair drawn below, choose the MORE STABLE molecule.

Does the  UNSTABLE molecule chosen below have  ANGLE STRAIN?

Does the  UNSTABLE molecule chosen below have  TORSIONAL STRAIN?

Does the  UNSTABLE molecule chosen below have  STERIC STRAIN?

Watch Solution

For the pair of molecules drawn below, choose the letter that corresponds to the  MORE STABLE molecule.

Does the  UNSTABLE molecule chosen below have  ANGLE STRAIN?

Does the  UNSTABLE molecule chosen below have  TORSIONAL STRAIN?

Does the  UNSTABLE molecule chosen below have  STERIC STRAIN?

Watch Solution

For the pair of molecules drawn below, choose the letter that corresponds to the MORE STABLE molecule.

Does the UNSTABLE molecule chosen above have ANGLE STRAIN?

A – Yes

B – No

Does the UNSTABLE molecule chosen above have TORSIONAL STRAIN?

A – Yes

B – No

Does the UNSTABLE molecule chosen above have STERIC STRAIN?

A – Yes

B – No

Watch Solution

Rank the following molecule in order of increasing stability (least stable to most stable)

A) 4, 1, 3, 2

B) 4, 3, 2, 1

C) 2, 3, 1, 4

D) 3, 2, 4, 1

E) 3, 2, 1, 4

Watch Solution

Which value is closest to the internal C-C-C bond angle in cyclohexane?

a) 90°

b) 100°

c) 110°

d) 120°

Watch Solution

What factor is responsible for a greater heat of combustion per CH 2 for cyclopropane than the heat of combustion per CH2 for cyclohexane?

a) Cyclohexane has a different hydrogen-to-carbon atom ratio than cyclopropane.

b) Cyclohexane is a strained ring relative to cyclopropane.

c) Cyclopropane is a strained ring relative to cyclohexane.

d) Cyclohexane has more carbon atoms than cyclopropane. 

Watch Solution