Why resonance effect does not occur at meta position?

And in benzonitrile, the resonance structures reduce the electron density on the ortho and para positions making the meta position relatively electron rich. Therefore, electrophiles would attack the meta position.

Why does Hyperconjugation does not occur at meta position?

Hyperconjugation as a rule dominates which increases the electron density of the aryl. This makes it less acidic because the conjugate base is now less stable. But when its meta-cresol, hyperconjugation no longer works.

Does resonance occur in meta position?

Answer: They increase the electron density inpositions ortho and para to the methyl group making these areas susceptible to attack by electrophiles. And in benzonitrile, the resonancestructures reduce the electron density on the ortho and para positionsmaking the meta position relatively electron rich.

What are ortho meta and para positions?

The terms ortho, meta, and para are prefixes used in organic chemistry to indicate the position of non-hydrogen substituents on a hydrocarbon ring (benzene derivative). The prefixes derive from Greek words meaning correct/straight, following/after, and similar, respectively.

Can you think why does no2 group shows its effect only at auto and para position and not at meta position?

Nitro group is an electron withdrawing group. Hence it pulls the ring electrons towards itself. Due to this process it decreases electron density at ortho and para position of the the ring. But meta position remains unaffected.

Why para is more stable than ortho?

While in para hydrogen, the proton nuclear spins are aligned antiparallel to each other. – These two forms of molecular hydrogen are also referred to as spin isomers. – Now, due to antiparallel spin arrangement, para hydrogen has less energy and thus, they are more stable than ortho hydrogen.

Which is more stable ortho meta or para?

Bottom line: the meta carbocation intermediate is more stable than either the ortho– or the para- intermediates. But it’s not because the substituent itself has any stabilizing effect on the meta– intermediate.

What determines ortho meta para?

If the relative yield of the ortho product and that of the para product are higher than that of the meta product, the substituent on the benzene ring in the monosubstituted benzene is called an ortho, para directing group. If the opposite is observed, the substituent is called a meta directing group.

Why para position is stable than ortho?

What is the resonance effect?

Resonance effect : The groups or atoms that have unbonded electrons i.e. lone pair of electrons on them, donate their electrons in the ring and they get delocalised. This is +R effect and it directs the coming groups to the ortho and para positions. E.g. NH3, CO groups

Why does propene show resonance structures when hyperconjugated?

This is possible due to free rotation of C-C bond so that the other C-H bonds can also participate in the hyperconjugation. Thus the propene molecule can show following resonance structures, which confer stability to it.

Is the meta position of benzene always ortho and para?

Now in case of electron withdrawing groups like Cyanide the meta substitution takes place due to -I effect as you can see in figure below. so in this case meta position is electro it is not always ortho and para, the direction depends on the substitution of group. The answer can be obtained through drawing resonating structures of benzene.

What is negnegative resonance?

Negative resonance or mesomeric effect (-M or -R): It is shown by substituents or groups that withdraw electrons by delocalization mechanism from rest of the molecule and are denoted by -M or -R. The electron density on rest of the molecular entity is decreased due to this effect. E.g. -NO 2, Carbony group (C=O), -C≡N, -COOH, -SO 3H etc.