Deck 18: Isomerism and Stereochemistry

Question 1

How many structural isomers exist for dibromochlorobenzene?

A) 1
B) 2
C) 4
D) 6

Answer 1

D

Question 2

From molecules, A-E, pick out the functional group isomers for hexanoic acid. Please select all that apply.

A) Molecule A
B) Molecule B
C) Molecule C
D) Molecule D
E) Molecule E

Answer 2

B, D

Question 3

Pick out the Newman projection which represents the most stable conformation of 1,2-diphenylethane:

A) A
B) B
C) C
D) D

Answer 3

B

Question 4

For the following conformers, A-D, pick out the one which represents the most stable conformer of molecule Z:

A) A
B) B
C) C
D) D

Question 5

Which one of the following alkenes exhibits geometrical isomerism?

A) 3-Methylpent-2-ene
B) Hex-1-ene
C) 2,3-Dimethylbut-2-ene
D) 2-Methylpent-2-ene
E) Cyclohexene

Question 6

For the following molecule, pick out its configuration:

A) (R)-
B) (S)-
C) (E)-
D) (Z)-

Question 7

For following two molecules, pick out the terminology which best describes their relationship:

A) Stereoisomers
B) Structural isomers
C) Conformers
D) Enantiomers
E) Diastereoisomers

Question 8

From the following molecules, A-E, pick out the one which is achiral:

A) Molecule A
B) Molecule B
C) Molecule C
D) Molecule D
E) Molecule E

Question 9

From the following molecules, A-E, pick out those with a plane of symmetry. Please select all that apply.

A) MoleculeA
B) Molecule B
C) Molecule C
D) Molecule D
E) Molecule E

Question 10

Using the Cahn-Ingold-Prelog (CIP) nomenclature, arrange the following groups, A-D, in order of decreasing priority (highest priority at the left):

A) A > C > B > D
B) D > A > B > C
C) B > A > D > C
D) C > A > B > D
E) D > B > A > C

Question 11

For the following molecule, pick out its configurations:

A) (R)- and (Z)-
B) (S)- and (Z)-
C) (R)- and (E)-
D) (S)- and (E)-

Question 12

For the following molecule, Z, pick out its enantiomer from molecules A-D:

A) A
B) B
C) C
D) D

Question 13

From the following molecules, A-D, pick out those which represent meso-2,3-dihydrobutane:

A) Molecule A
B) Molecule B
C) Molecule C
D) MoleculeD

Question 14

For a compound to be classed as meso-; what is the required minimum number of chiral centres?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 15

From the following molecules, A-D, pick out the one which is meso:

A) Molecule A
B) Molecule B
C) Molecule C
D) Molecule D

Question 16

From the following molecules, A-D, pick out those that are chiral. Please select all that apply.

A) Molecule A
B) Molecule B
C) Molecule C
D) Molecule D

Question 17

From the following molecules, A-D, pick out the one which is chiral and contains at least one chiral centre:

A) Molecule A
B) Molecule B
C) Molecule C
D) MoleculeD

Question 18

The (R)-enantiomer of ibuprofen has a specific rotation of [ $\alpha$ ] ²⁰_D= -59. What proportion of enantiomers would be required to prepare an optically impure sample of ibuprofen with a specific rotation of +29.50?

A) 25% (S)-, 75% (R)-
B) 50% (S)-, 50% (R)-
C) 67% (S)-; 33% (R)-
D) 75% (S)-, 25% (R)-
E) 50% (S)-, 0% (R)-

Question 19

From the following reactions, A-D, pick out the one which involves racemisation:

A) A
B) B
C) C
D) D

Question 20

From the following reactions, A-D, pick out the one which involves a diastereoselective addition:

A) A
B) B
C) C

Question 21

What is the relationship between these two molecules? Please select all that apply.

A) Stereoisomer
B) Enantiomer
C) Position isomer
D) Structural isomer

Question 22

What is the relationship between these two molecules? Please select all that apply.

A) Stereoisomer
B) Enantiomer
C) Chain isomer
D) Structural isomer

Question 23

What is the relationship between these two molecules? Please select all that apply.

A) chain isomers
B) position isomers
C) enantiomers
D) (E)-(Z) isomers

Question 24

Assign this alkene as (E) or (Z).

A) (E)
B) (Z)
C) Type option here
D) Type option here

Question 25

Assign the following according to the Cahn- Ingold-Prelog (CIP) sequence rules.

A) (R)
B) (S)
C) (E)
D) (Z)