Chirality and Optical Activity
Chemistry ⇒ Carbon and Organic Chemistry
Chirality and Optical Activity starts at 11 and continues till grade 12.
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A compound has three chiral centers. What is the maximum number of stereoisomers possible?
A sample of a chiral compound has a specific rotation of –10°. What does the negative sign indicate?
A solution contains 70% of the (+) enantiomer and 30% of the (–) enantiomer. What is the enantiomeric excess?
Assign the R or S configuration to a chiral center if the priority order of the groups attached is: Br > OH > CH3 > H, and the lowest priority group (H) is pointing away from you, with the order Br → OH → CH3 going clockwise.
Define optical activity.
Describe the Cahn-Ingold-Prelog priority rules used in assigning R and S configurations.
Assign the R or S configuration to a chiral center if the priority order of the groups attached is: Br > OH > CH3 > H, and the lowest priority group (H) is pointing away from you, with the order Br → OH → CH3 going clockwise.
The specific rotation of a compound is +20°. If the observed rotation for a sample is +5°, what is the percentage of the (+) enantiomer in the sample, assuming the rest is the (–) enantiomer?
Which of the following compounds is achiral? (1) 2-chloropropane (2) 2-chlorobutane (3) 3-chloropentane (4) 2-bromobutane
Which of the following compounds is chiral? (1) 2-butanol (2) 2-propanol (3) 1-butanol (4) 2,2-dimethylpropanol
Which of the following is a chiral molecule? (1) 1,1-dichloroethane (2) 1,2-dichloroethane (3) 2-chlorobutane (4) 2,2-dichloropropane
Which of the following is a meso compound? (1) 2,3-dibromobutane (2) 2-butanol (3) 2,3-dimethylbutane (4) 1,2-dibromoethane
A carbon atom bonded to four different groups is called a(n) ________ center.
A compound rotates plane-polarized light to the left. It is said to be ________.
A molecule with two chiral centers can have a maximum of ________ stereoisomers.
Fill in the blank: The number of possible stereoisomers for a molecule with n chiral centers is ________.
True or False: A molecule with a plane of symmetry is always achiral.
True or False: A molecule with no chiral centers can never be chiral.
True or False: A racemic mixture is optically inactive.
True or False: All molecules with a stereocenter are chiral.
