Q: Which of the following bases would most likely favor the formation of the Hofmann product in an E2 elimination?

tert-butoxide ($$\text{(CH}_3)_3\text{CO}^-)$$

Question 1

Which hybridization is found in the carbon atoms of ethylene, and what is the resulting molecular geometry?

Accepted Answer

sp2 hybridization; trigonal planar geometry

Question 2

What is the general formula for an alkene, and how does it differ from an alkane?

Accepted Answer

Alkene: $$C_nH_{2n}$$; Alkane: $$C_nH_{2n+2}$$

Question 3

Calculate the number of elements of unsaturation for a compound with the formula $$C_6H_7N.$$

Accepted Answer

4

Question 4

Which statement best explains why cis and trans isomers of alkenes cannot be interconverted at room temperature?

Accepted Answer

Rotation around the double bond is prevented by the pi bond, which must be broken to allow interconversion.

Question 5

Which of the following compounds would NOT exhibit cis/trans (geometric) isomerism?

Accepted Answer

1-pentene

Question 6

According to Zaitsev’s rule, which product will predominate in the E2 elimination of 2-bromobutane with a small base?

Accepted Answer

trans-2-butene

Question 7

Which of the following statements about the boiling points of cis and trans alkenes is correct?

Accepted Answer

Cis alkenes have higher boiling points due to greater dipole moments.

Question 8

Which rule states that a bridged bicyclic compound cannot have a double bond at a bridgehead position unless one of the rings contains at least eight carbon atoms?

Accepted Answer

Bredt’s Rule

Question 9

What is the correct IUPAC name for the compound shown below?

$$	ext{CH}_2=CHCH_2CH_2CH_2CH_2CH_2CH_2Br$$

with double bonds at positions 3 and 5, and a bromine at position 3, with (3Z,5E) stereochemistry.

Accepted Answer

(3Z,5E)-3-bromo-3,5-octadiene

Question 10

Which of the following bases would most likely favor the formation of the Hofmann product in an E2 elimination?

Accepted Answer

tert-butoxide ($$	ext{(CH}_3)_3	ext{CO}^-)$$

Question 11

A compound with the formula $$C_4H_7Br$$ has how many elements of unsaturation?

Accepted Answer

1

Question 12

Which of the following statements about the E1 elimination mechanism is TRUE?

Accepted Answer

The rate-determining step is the formation of the carbocation.

Question 13

Which of the following is a correct application of the Cahn–Ingold–Prelog rules for E/Z nomenclature?

Accepted Answer

Assign priorities based on atomic number; if the highest priority groups are on the same side, the isomer is Z.

Question 14

Which of the following statements about cycloalkenes is correct?

Accepted Answer

Trans cycloalkenes are not stable unless the ring has at least eight carbons.

Question 15

Which physical property of alkenes increases with molecular mass, but decreases with branching?

Accepted Answer

Boiling point

Question 16

What is the major product when 2-bromo-2-methylbutane undergoes E2 elimination with tert-butoxide?

Accepted Answer

2-methyl-1-butene (Hofmann product)

Question 17

Which of the following is NOT a method for synthesizing alkenes?

Accepted Answer

Hydration of alkenes

Question 18

Which of the following statements about elimination reactions is correct?

Accepted Answer

High temperature favors elimination over substitution.

Question 19

During the dehydration of alcohols using concentrated $$	ext{H}_2	ext{SO}_4$$, which mechanism is followed and what is the major product?

Accepted Answer

E1 mechanism; most substituted alkene (Zaitsev product)

ch 7 Structure and Synthesis of Alkenes: Comprehensive Study Notes

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