Question 1

Which of the following Newman projections of n-butane corresponds to the lowest potential energy conformation?

Accepted Answer

Anti conformation with methyl groups 180° apart

Question 2

Given the following reaction: $$\mathrm{CH_3CO_2H + HCN \rightarrow CH_3CO_2CN + H_2O}$$, which type of reaction mechanism is most likely involved?

Accepted Answer

Nucleophilic substitution

Question 3

Which of the following statements best explains why $$\mathrm{NH_2$} is $$more water soluble than $$\mathrm{C(CH_3$)_3}$$?

Accepted Answer

Because $$\mathrm{NH_2$}$$ can form hydrogen bonds with water

Question 4

Assign the correct hybridization to the positively charged carbon in the benzyl carbocation $$\mathrm{C_6H_5CH_2^+}.$$

Accepted Answer

$$sp^2$$

Question 5

Which of the following compounds is chiral?

Accepted Answer

$$\mathrm{H_2C(OH)CH(OH)CO_2H} ($$with all groups different at the central carbon)

Question 6

Which of the following is the correct IUPAC name for the molecule shown: a heptane chain with ethyl and two methyl groups at position 4?

Accepted Answer

3-ethyl-4,4-dimethylheptane

Question 7

In the free radical bromination of tert-butane, which step is the initiation step?

Accepted Answer

$$\mathrm{Br_2$ \rightarrow 2Br^\cdot}$$

Question 8

Which of the following pairs are enantiomers?

Accepted Answer

Two molecules with opposite configurations at all chiral centers

Question 9

Which functional group is present in the molecule $$\mathrm{CH_3CH_2OH}$$?

Accepted Answer

Alcohol

Question 10

Which of the following acids is the strongest according to the provided table of $$pK_a$$ values?

Accepted Answer

$$\mathrm{HCl}$$

Question 11

What is the relationship between the two molecules shown below, each with two chiral centers, but only one center inverted?

Accepted Answer

Diastereomers

Question 12

Which of the following is the correct Fischer projection for the $$R$$ configuration of the given molecule?

Accepted Answer

A projection with the lowest priority group on a vertical bond and priorities arranged clockwise

Question 13

Which of the following elements has the highest electronegativity according to the Pauling scale?

Accepted Answer

Fluorine

Question 14

Which conformation of n-butane is responsible for the highest energy maximum in the potential energy diagram?

Accepted Answer

Eclipsed with methyl groups aligned

Question 15

Which of the following is a nucleophile in the reaction $$\mathrm{CH_3CO_2H + HCN \rightarrow CH_3CO_2CN + H_2O}$$?

Accepted Answer

$$\mathrm{HCN}$$

Question 16

Which of the following is true about meso compounds?

Accepted Answer

They have chiral centers but are achiral due to an internal plane of symmetry

Question 17

Which of the following best describes the hybridization of the central carbon in ethyne ($$\mathrm{C_2H_2}$$)?

Accepted Answer

$$sp$$

Question 18

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties

Question 19

Which of the following is the correct mechanism for the propagation step in the free radical bromination of tert-butane?

Accepted Answer

$$\mathrm{Br^\cdot + (CH_3$)_3C-H \rightarrow (CH_3$)_3C^\cdot + HBr}$$

Question 20

Which of the following is the correct order of acid strength from strongest to weakest according to the provided table?

Accepted Answer

$$\mathrm{HCl \u003e CH_3CO_2H \u003e H_2O \u003e NH_3$}$$

Organic Chemistry: Conformations, Mechanisms, Stereochemistry, and Acid-Base Properties

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