Question 1

Which of the following statements best describes a structural isomer?

Accepted Answer

Molecules with the same atomic composition but different atom connectivity.

Question 2

Which of the following is true about geometric (cis/trans) isomers in alkenes?

Accepted Answer

They result from restricted rotation around a double bond.

Question 3

According to the Cahn-Ingold-Prelog (CIP) convention, how is the priority of substituents determined when assigning R/S configuration?

Accepted Answer

By the atomic number of the atoms directly attached to the stereocentre.

Question 4

Which of the following molecules is chiral?

Accepted Answer

A molecule with a stereocentre and no symmetry elements.

Question 5

Enantiomers are best described as:

Accepted Answer

Non-superimposable mirror images of each other.

Question 6

Which property is used to distinguish enantiomers in the laboratory?

Accepted Answer

Rotation of plane-polarized light.

Question 7

A polarimeter is used to measure which property of chiral molecules?

Accepted Answer

Their ability to rotate the plane of polarized light.

Question 8

Which of the following statements about the CORN law is correct?

Accepted Answer

It helps determine whether amino acids are (L) or (D) by the orientation of COOH, R, NH2, and H.

Question 9

Which of the following is NOT a requirement for a molecule to be chiral?

Accepted Answer

It must have at least two identical substituents.

Question 10

Which of the following best describes the difference between structural isomers and stereoisomers?

Accepted Answer

Structural isomers have different atom connectivity, while stereoisomers have the same atom connectivity but different spatial arrangement.

Question 11

Which configuration is assigned when the sequence from highest to lowest priority substituent (1 → 2 → 3) is clockwise, with the lowest priority group pointing away from the observer?

Accepted Answer

$$R$$

Question 12

Which of the following statements about the E/Z notation for alkenes is correct?

Accepted Answer

E/Z notation is assigned based on the priority of substituents attached to the double bond.

Question 13

Which of the following is a correct application of the Cahn-Ingold-Prelog (CIP) rules?

Accepted Answer

Assigning E/Z configuration to alkenes based on the highest atomic number substituents on each carbon of the double bond.

Question 14

Which of the following is true about the (D) and (L) notation for amino acids?

Accepted Answer

It is based on the structural comparison to glyceraldehyde.

Question 15

Which of the following statements about sucrose is correct?

Accepted Answer

Sucrose is chiral and rotates the plane of polarized light.

Question 16

A student is given a sample of an unknown sugar and uses a polarimeter to measure its optical rotation. The sample rotates plane-polarized light to the right. Which of the following is true?

Accepted Answer

The sugar is optically active.

Question 17

Which of the following is NOT a stereoisomer?

Accepted Answer

Structural isomer.

Question 18

Which of the following best explains why geometric isomers exist in alkenes?

Accepted Answer

Because of restricted rotation around the double bond.

Question 19

Which of the following is a necessary condition for a carbon atom to be a stereocentre?

Accepted Answer

It must be bonded to four different substituents.

Question 20

Which of the following is true regarding the assignment of R/S configuration using the CIP rules?

Accepted Answer

The sequence from highest to lowest priority is traced, and if it is clockwise, the configuration is R.

Stereochemistry: Isomerism and Chirality

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