This reaction, which is the hydrolysis of an amide, is favored in strong acid. Acid protonates the
carbonyl oxygen, which increases the electrophilicity of the carbonyl carbon. This allows water to
serve as the nucleophile, attacking the bond and hydrolyzing the molecule.12 . D
This molecule is more stable with a positive charge than a straight-chain alkane due to the
conjugation of the benzene ring. This permits delocalization of the charge through resonance.
Although induction, choice (C), does have an effect on the stabilization of the molecule, this
effect is much less significant than the impact of having a conjugated system. The
electronegativity of nitrogen, choice (B), which primarily affects induction, is also not a vital
component of the stabilization by this molecule of a positive charge because oxygen is more
electronegative. Steric hindrance, choice (A), would affect the reactivity of a molecule, but not its
ability to stabilize charge.
13 . D
The molecule shown, γ-nonalactone, is a cyclic ester, also called a lactone. This molecule could
arise from intramolecular attack in a γ-hydroxycarboxylic acid.
14 . A
In order to prepare butyl acetate from butanol, we need to perform a nucleophilic acyl
substitution reaction. If the product is an ester, we need to start with a reactant that is more
reactive than the ester itself, or the reaction will not proceed. Anhydrides are more reactive than
esters, but amides are less reactive, eliminating choices (C) and (D). Reaction with propanoic
anhydride, as in choice (B), would result in butyl propanoate.
15 . D
The presence of water in an esterification reaction would likely revert some of the desired esters
back into carboxylic acids. Small carboxylic acids, like formic or acetic acid, are easily dissolved in
water, eliminating choice (A). The polarity of water plays little role in affecting the leaving group;
if anything, water can be used to increase the electrophilicity of the carbonyl carbon by
protonating the carbonyl oxygen—eliminating choice (B). Finally, this is a nucleophilic
substitution mechanism, not a nucleophilic addition mechanism, as mentioned in choice (C).
Further, hydrogen bonding would likely augment the reaction.