Top 150+ Solved Pharmaceutical Organic Chemistry 3 MCQ Questions Answer
Q. 1 Hexane and 3-methylpentane are examples of:
a. Enantiomers.
b. Stereoisomer.
c. Diastereomers.
d. Constitutional isomers.
Q. Cis-trans isomers are:
a. Diastereomers.
b. Enantiomers.
c. Geometric isomers.
d. Constitutional isomers.
Q. (2R,4S) –2,4–Dichloropentane and (2S,4R)-2,4-dichloropentane are:
a. Enantiomers
b. Diastereomers
c. identical
d. conformational isomers
Q. Which of the following molecules is achiral?
a. (2R,3R)-2,3-Dichloropentane
b. (2R,3S)-2,3-Dichloropentane
c. (2S,4S)-2,4-Dichloropentane
d. (2S,4R)-2,4-Dichloropentane
Q. Which statement is not true for a meso compound?
a. The specific rotation is 0º.
b. There are one or more planes of symmetry.
c. More than one stereogenic center must be present.
d. The stereo chemical labels, (R) and (S), must be identical for each stereogenic centre.
Q. 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
Q. What is the percent composition of a mixture of (S)-(+)-2-butanol,[!] D/25 = +13.52º, and (R)-(-)-2-butanol,[!] D/25 = -13.52º, with a specific rotation [!] D/25 = +6.76º?
a. 75%(R) 25%(S)
b. 25%(R) 75%(S)
c. 50%(R) 50%(S)
d. 67%(R) 33%(S)
Q. Which one of the following can exist in optically active forms?
a. cis-1,3-Dichlorocyclohexane
b. trans-1,3-Dichlorocyclohexane
c. cis-1,4-Dichlorocyclohexane
d. tr
Q. Which of these is a comparatively insignificant factor affecting the magnitude of Specific optical rotation?
a. Concentration of the substance of interest
b. Purity of the sample
c. Temperature of the measurement
d. Length of the sample tube
Q. What can be said with certainty if a compound has [!] D/25 = -9.25º ?
a. The compound has the (S) configuration.
b. The compound has the (R) configuration.
c. The compound is not a meso form.
d. The compound possesses only one stereogenic center.
Q. An alkane which can exhibit optical activity is:
a. Neopentane
b. Isopentane
c. 3–Methylpentane
d. 3–Methylhexane
Q. In the absence of specific data, it can only be said that (R)–2–bromopentane is:
a. Dextrorotatory (+).
b. Levorotatory (–).
c. Optically inactive.
d. Chiral.
Q. If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15º in a 2 dmtube, the specific rotation is:
a. +50º
b. +25º
c. +15º
d. +7.5º
Q. Which compound would show optical activity?
a. cis 1,4- Dimethylcyclohexane
b. trans 1,4- Dimethylcyclohexane
c. cis 1,4- Dimethylcycloheptane
d. tr