Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions?()
A. The carbonyl carbon of an ester is more electrophilic than that of an aldehyde.
B. Aldehydes are more sterically hindered than esters.
C. Once the nucleophile adds to an aldehyde, the tetrahedral intermediate is too sterically hindered to eliminate one of the attached groups.
D. The ester carbonyl carbon is sp3 hybridized while the aldehyde carbonyl carbon is sp2 hybridized.
E. Once the nucleophile adds to an aldehyde, neither H- nor R- can be eliminated because they are poor leaving groups.
查看答案
Which of the following alcohols can be prepared by the reaction of methyl formate with excess Grignard reagent?()
A. 1-pentanol
B. 2-pentanol
C. 3-pentanol
D. 2-methyl-2-pentanol
E. 3-methyl-3-pentanol
What is the hybridization and geometry of the carbonyl carbon in carboxylic acids and their derivatives?()
A. sp3, tetrahedral
B. sp2, trigonal planar
C. sp2, tetrahedral
D. sp3, trigonal planar
E. sp, trigonal planar
Which of the following compounds has the lowest boiling point?()
A. 1-butanol
B. butanoic acid
C. butanenitrile
D. methyl propanoate
E. butanamide
In nucleophilic acyl substitution,()
A. protonation of the carbonyl is followed immediately by loss of the leaving group.
B. loss of the leaving group is followed by rearrangement of the carbocation.
C. addition to the carbonyl by a nucleophile is followed by loss of the leaving group.
D. ester hydrolysis is followed by deprotonation.
E. an SN2 reaction occurs.
微信支付 
支付宝支付