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I am assuming that you are refering to a benzene ring, with some sort of subsituent group attached?
If this is the case, the electron density of a benzene ring can be altered by attaching different substiuent groups to it. A group can either push electron density into the ring or withdraw it. If electron density is pushed into the ring from the substituent, either along a sigma bond or through the pi system, then the density is concentrated at the orthro and para positions due to the resonance structures formed when attacked by an electrophile at either of these postions.
Very difficult to explain properly without pictures, I am sorry.
Wikipedia has a page, with more detail under the Ortho/para director heading:
http://en.wikipedia.org/wiki/Electrophilic_aromatic_substitution
What else can I help you with?
Why methyl attached to benzene is ortho-para director group?
This group attached to benzene ring acts as the ortho-para directing group due to Hyperconjugation.
Why ortho benzoic acid is more acidic than para osomer?
Nitro group (-NO2), having -I and -R effect, is an electron withdrawing and deactivating group. Due to both these effects, it decreases electron density around the -COOH group of substituted(ortho, meta & para) benzoic acids and releases H+ ions, making these acidic. The nitrobenzoic acid which releases H+ group more easily is the most acidic. Due to ortho effect, ortho acids are more acidic than all other substituted acids(even if an electron donating group is present at the ortho position. The only exception is -NH2 group, in which ortho- aminobenzoic acid is NOT the strongest acid). Regarding acidity of meta and para acids, consider I and R effects. Inductive effects of meta and para acids reduce electron density around -COOH group, whereas resonance does not occur at meta position. It only occurs at para position, making the nitro group at para position a more strong withdrawer of electrons. Thus para-nitro benzoic acid is more acidic than meta-nitro benzoic acid. In short, the higher acidity of p-nitrobenzoic acid compared to m-nitrobenzoic acid is attributed to its -I and -R effect.
What are the differences between activating and deactivating groups in electrophillic aromatic substitution?
Activating groups donate electron density either through inductive effects or resonance. They are usually ortho and para directed, which means the subsequent groups added will either be in the 2 or 4 position relative to the functional group. It is easy to determine if a functional group is activating if it electronegative molecules are single bonded. Examples: alkyl groups (-CH3), alkoxyl (-OCH3), amino (-NH2), thio (-SH), The exception to the trend that activating groups = ortho/para are halides. Halides are deactivating groups because of strong electronegativity, but they are also ortho and para. Molecules that are double bonded like -NO2, HSO4, and halides are deactivating. They are meta directed, adding molecules at the 3 position.
Ortho effect on acidity of carboxylic acid?
The ortho effect refers to the decrease in acidity of a carboxylic acid when bulky substituents are present at the ortho positions of the phenyl ring. This is due to the steric hindrance caused by the bulky groups, which makes it more difficult for the carboxylate anion to be stabilized, resulting in lower acidity.
What do you mean by the donor and acceptor ions?
Donor group are ortho-para directory groups that means increases in pai density of ortho para directory. Adaptor group meta directing groups that means increases in pai density of meta directing groups.
Activating and deactivating group of Ortho para and meta director groups Explain?
Ortho, para, and meta-directing groups are electron-donating or electron-withdrawing substituents in aromatic compounds. Activating groups increase the electron density on the ring, making it more reactive towards electrophilic substitution. Deactivating groups reduce the electron density on the ring, making it less reactive. The specific positions favored for substitution (ortho, para, or meta) depend on the nature of the substituent and its effects on the ring.
Why halogens that is deactivate group attack to ortho and para position?
Halogens are electron-withdrawing groups due to their high electronegativity, which reduces the electron density at the ortho and para positions of an aromatic ring. This decreased electron density makes it less favorable for electrophilic aromatic substitution reactions to occur at those positions, leading to deactivation of those positions.
Why methyl attached to benzene is ortho-para director group?
This group attached to benzene ring acts as the ortho-para directing group due to Hyperconjugation.
Why nitroso in nitrosobenzene deactivating yet ortho para directing?
Nitroso group (-NO) is deactivating because it withdraws electron density from the benzene ring due to its electronegativity. However, it is ortho para directing because it can donate electrons into the benzene ring through resonance, enhancing the electron density at the ortho and para positions.
Why are halogens ortho para directors but deactivating in electrophilic aromatic substitution reactions?
Halogens are ortho para directors because they direct incoming groups to the ortho and para positions on the benzene ring due to their electron-withdrawing nature. However, they are deactivating in electrophilic aromatic substitution reactions because they withdraw electron density from the benzene ring, making it less reactive towards electrophiles.
Why Chlorobenzene is orthoparadirecting?
Chlorobenzene is ortho-para directing because the lone pairs on the chlorine atom can donate electron density through resonance, stabilizing the σ-complex formed during electrophilic aromatic substitution. This leads to preferential attack at the ortho and para positions of the benzene ring.
Why is anisole ortho and para director towards electrophile substitution reaction?
Anisole is ortho and para directing in electrophilic aromatic substitution reactions because the lone pairs on the oxygen atom can donate electron density to the ring through resonance, stabilizing the carbocation intermediate formed during the reaction at the ortho and para positions. This makes those positions more favorable for electrophilic attack.
Why is -NHCOCH3 a less powerful ortho para-directing group than -NH2?
-NHCOCH3 is a less powerful ortho para-directing group compared to -NH2 because the acetyl group (-COCH3) is electron-withdrawing and deactivates the benzene ring by resonance. This decreases the electron density on the benzene ring, making it less likely for electrophilic substitution to occur at the ortho and para positions. In contrast, -NH2 is electron-donating and activates the ring, making it more susceptible to electrophilic substitution at the ortho and para positions.
Why nitrobenzene in the meta position?
Nitrobenzene typically favors substitution in the meta position due to the strong electron-withdrawing nature of the nitro group. This group directs incoming electrophiles to the meta position by decreasing electron density at the ortho and para positions through resonance effects.
Why does chlorobenzene give ortho and para products during electrophilic substitution reaction?
As there is an availability of lone pair of electrons on chlorine, it directs the benzene ring towards electrophilic substitution at ortho and para positions.. When we will draw the resonating structures of chloro benzene,we will see that negative charge resides at orho and para positions..
Why ortho chlorobenzoic acid is stronger than benzoic acid?
Ortho chlorobenzoic acid is stronger than benzoic acid due to the electron-withdrawing effect of the chlorine atom. This increases the acidity of ortho chlorobenzoic acid by stabilizing the conjugate base through delocalization of the negative charge. In contrast, benzoic acid has no such electron-withdrawing substituent.
Why nitro group is formed on ortho and para position?
orientation of incoming Nitro group is destined by already present group on benzene ring . if already present group is electron donating group, it will promote electron density at ortho and para position and , therefore, nitro group is formed on ortho and para position.
