Question 1

Which of the following molecules are chiral?&#10; &#10;A) only II&#10;B) only III&#10;C) II and III&#10;D) I, II, and III

Accepted Answer

only II&#10;

Question 2

How many stereogenic centers are there in the following molecule?&#10; &#10;A) only 1&#10;B) two&#10;C) three&#10;D) four

Accepted Answer

two&#10;

Question 3

What is the IUPAC name of the following compound?&#10; &#10;A) (2S, 3S)-2,3-dibromopentane&#10;B) (2S, 3R)-2,3-dibromopentane&#10;C) (2R, 3S)-2,3-dibromopentane&#10;D) (2R, 3R)-2,3-dibromopentane

Accepted Answer

(2R, 3R)-2,3-dibromopentane&#10;

Question 4

What is the relationship between the following two molecules?&#10; &#10;A) identical&#10;B) enantiomers&#10;C) diastereomers&#10;D) constitutional isomers

Accepted Answer

The answer of What is the relationship between the following...

Question 5

What are the configurations of carbons 2 and 3 in the Fischer projection below?&#10; &#10;A) 2R, 3R&#10;B) $2 \mathrm{R}, 3 \mathrm{~S}$&#10;C) 2S, 3R&#10;D) 2S, 3S

Accepted Answer

The answer of What are the configurations of carbons 2...

Question 6

Compound $\mathrm{X}, \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}$, is optically active. The compound consumes one equivalent of hydrogen to give $\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{O}$. The hydrogenation product is also optically active. Which compound below matches the information?&#10;&#10;A) &#10; &#10;B) &#10; &#10;C)&#10; &#10;D) &#10;

Accepted Answer

The answer of Compound $\mathrm{X}, \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}$, is optically...

Question 7

A pure sample of (S)-phenylalanine has a specific rotation of $+70^{\circ}$ . A mixture of the two enantiomers of phenylalanine has a specific rotation of $+7.0^{\circ}$ . What are the percentages of the $S$ and $R$ enantiomers in the mixture?

A)

95 \% \mathrm{~S}, 5 \% \mathrm{R}

B)

90 \% \mathrm{~S}, 10 \% \mathrm{R}

C)

55 \% \mathrm{~S}, 45 \% \mathrm{R}

D)

52.5 \% \mathrm{~S}, 47.5 \% \mathrm{R}

Accepted Answer

The answer of A pure sample of (S)-phenylalanine has a...

Question 8

Which of the following has a meso stereoisomer?
I. 2,4-dichloropentane
II. 1,3-dimethylcyclopentane
III. 2,3-dichloropentane

A) only I
B) only II
C) I and III
D) I and II

Accepted Answer

I. 2,4-dichloropentane and II. 1,3-dimethylcyclopentane can have meso stereoisomers because they can have a plane of symmetry when arranged properly. III. 2,3-dichloropentane cannot have a meso form due to its asymmetric carbon atoms being adjacent, making it impossible to have a plane of symmetry.

Question 9

How many stereoisomers are there of D-fructose (including D-fructose), shown below?&#10;  &#10;A) four&#10;B) six&#10;C) eight&#10;D) twelve

Accepted Answer

The answer of How many stereoisomers are there of D-fructose...

Question 10

Which compound below has no stereoisomers?&#10;A) 1,2-dichlorobutane&#10;B) 1,3-dichlorobutane&#10;C) 2,3-dichlorobutane&#10;D) 1,4-dichlorobutane

Accepted Answer

1,4-dichlorobutane has no stereoisomers because it lacks chiral centers and does not have any double bonds that could lead to cis-trans isomerism.

Question 11

Which one of the following is a diastereomer of (2R,3R)-2,3-dibromopentane?&#10;A) (2S,3S)-2,3-dibromopentane&#10;B) (2S,3R)-2,3-dibromopentane&#10;C) R-1,2-dibromopentane&#10;D) (2R,4R)-2,4-dibromopentane

Accepted Answer

The answer of Which one of the following is a...

Question 12

The tartaric acid found in fruits, when isolated, exhibits $[\alpha]=+12^{\circ}$. Which configuration is NOT possible for this naturally-occurring material?&#10; &#10;A) R, R&#10;B) R, S&#10;C) S, S&#10;D) there is no way to tell

Accepted Answer

The answer of The tartaric acid found in fruits, when...

Deck 7: Chirality