This set of Organic Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Meso Structures”.
1. Which of the following is the definition of a meso compound?
a) A molecule with chirality centers which is chiral
b) A chiral compound with more than one chirality center
c) A diastereomer with no chirality centers
d) A molecule with chirality centers which is not chiral
View Answer
Explanation: Meso compounds are not chiral. Molecule with chirality centers which is chiral are false. So, other statements are false.
2. A compound whose molecules are superimposable on their mirror images even though they contain asymmetric carbon atoms is called
a) A threo compound
b) A meso compound
c) A unsymmetric compound
d) An erythro compound
View Answer
Explanation: Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
3. Which of the following compounds is a meso compound?
a) (2R,3R)-dibromobutane
b) (2R,3S)-dibromobutane
c) (2R,3S)-3-bromo-2-butanol
d) (2R,3R)-3-bromo-2-butanol
View Answer
Explanation: (2R,3S)-Dibromobutane is superimposable on its mirror image, so it is achiral (i.e., not chiral). Achiral molecules which have chirality centers are called meso compounds. Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
4. Which statement is not true for a meso compound?
a) The specific rotation is 0°
b) There are one or more planes of symmetry
c) A single molecule is identical to its mirror image
d) The stereochemical labels, (R) and (S), must be identical for each stereogenic center
View Answer
Explanation: Statement stereochemical labels, (R) and (S), must be identical for each stereogenic center is not true about meso compounds, stereochemical labels, (R) and (S), can or cannot be identical for each stereogenic center.
5. Which is a meso compound?
a) (2R,3R)-2,3-Dibromobutane
b) (2R,3S)-2,3-Dibromopentane
c) (2R,4R)-2,4-Dibromopentane
d) (2R,4S)-2,4-Dibromopentane
View Answer
Explanation: (2R,4S)-Dibromopentane is superimposable on its mirror image, so it is achiral (i.e., not chiral). Achiral molecules which have chirality centers are called meso compounds. Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
6. Which of the following is a mesocompound?
a) I
b) II
c) III
d) IV
View Answer
Explanation: Compound I is superimposable on its mirror image, so it is achiral. Achiral molecules which have chirality centers are called meso compounds. Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
7. The given compound is meso compound.
a) True
b) False
View Answer
Explanation: The given compound is superimposable on its mirror image, so it is achiral. Achiral molecules which have chirality centers are called meso compounds. Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
8. Which of the following is(are) not meso compound(s)?
a) II
b) II and III
c) I and III
d) I and II
View Answer
Explanation: Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
9. Which of the following is(are) not meso compound(s)?
a) I
b) II and III
c) I and III
d) I and II
View Answer
Explanation: Meso compounds are possible if two (or more) chirality centers in a molecule have the same set of four substituents. Examination of molecular models might help you when examining stereoisomers.
10. Which is the meso isomer of butane-1,2,3,4-tetraol?
a)
b)
c)
d) 
View Answer
Explanation: If we redraw each structure with the OH groups (for example) on C2 and C3 eclipsed, or re-write the structures as Fischer projections, then we can see more easily which structure has a mirror plane between C2 and C3. And this condition will satisfy the meso compound.
Sanfoundry Global Education & Learning Series – Organic Chemistry.
To practice all areas of Organic Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.
- Check Organic Chemistry Books
- Practice Chemical Engineering MCQs
- Apply for Chemical Engineering Internship
- Check Chemical Engineering Books
