Concept explainers
For each of the following substituted benzenes: [1]
a. Does the substituent donate or withdraw electron density by an inductive effect?
b. Does the substituent donate or withdraw electron density by a resonance effect?
c. On balance, does the substituent make a benzene ring more or less electron rich than benzene itself?
d. Does the substituent activate or deactivate the benzene ring in electrophilic
(a)
Interpretation: The substituents present on the given benzene donate or withdraw electron density by an inductive effect is to be predicted.
Concept introduction: The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron deficient chemical species that contains positive charge are known as electrophile. In electrophilic aromatic substitution reaction, electrophile takes the position of hydrogen atom by attacking the electron rich carbon atom of benzene.
Answer to Problem 18.47P
The substituent in
Explanation of Solution
The inductive effect appears in a molecule due to the difference in electron negativity of atoms. The groups attached to benzene ring in the given compound are
The electron negativity of bromine is more than carbon atom. Hence, the substituent in
The electron negativity of nitrogen is more than carbon atom. Hence, the substituent in
The electron negativity of oxygen is more than carbon atom. Hence, the substituent in
The substituent in
(b)
Interpretation: The substituents present on the given benzene donate or withdraw electron density by a resonance effect is to be predicted.
Concept introduction: The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron deficient chemical species that contains positive charge are known as electrophile. In electrophilic aromatic substitution reaction, electrophile takes the position of hydrogen atom by attacking the electron rich carbon atom of benzene.
Answer to Problem 18.47P
The substituent in
Explanation of Solution
The positive resonance effect is observed when the substituent present on a benzene ring donates its lone pair of electrons. Whereas, the negative resonance effect is observed, when the substituents present on a benzene ring pull its electrons towards itself.
The bromine atom attached to a benzene ring in
The carbon atom of
Figure 1
Therefore, the substituent in
The oxygen atom attached to a benzene ring in
The substituent in
(c)
Interpretation: The substituents make benzene ring more or less electron than benzene itself is to be predicted.
Concept introduction: The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron deficient chemical species that contains positive charge are known as electrophile. In electrophilic aromatic substitution reaction, electrophile takes the position of hydrogen atom by attacking the electron rich carbon atom of benzene.
Answer to Problem 18.47P
Substituents
Explanation of Solution
The electron donating groups or activating groups make benzene ring more electron rich than benzene itself, whereas the electron withdrawing groups or deactivating groups make benzene ring less electron rich than benzene itself.
The
Substituents
(d)
Interpretation: The substituents activate or deactivate the benzene ring in electrophilic aromatic substitution is to be predicted.
Concept introduction: The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron deficient chemical species that contains positive charge are known as electrophile. In electrophilic aromatic substitution reaction, electrophile takes the position of hydrogen atom by attacking the electron rich carbon atom of benzene.
Answer to Problem 18.47P
Substituents
Explanation of Solution
The electron donating groups activate the benzene ring in electrophilic aromatic substitution, whereas the electron withdrawing groups deactivate the benzene ring in electrophilic aromatic substitution.
The
Substituents
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Chapter 18 Solutions
ORGANIC CHEMISTRY W/ ACCESS >IC<
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