Why Hyperconjugation does not work at meta position?
Ans. In hyperconjuagation basically we talk about interactions of sigma bond with empty or partially filled p- orbital ,so if we remember that diagram in which no +charge was appearing at meta positions.
Why no2 group shows its effect only at ortho 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.
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.
Is resonance possible in meta position?
For the meta substituted carbocation resonance structures, there are three possible resonance froms that are secondary carbocations. Therefore, the two major products of the reaction of a monosubstituted benzene ring with an electron donating group and additional electrophile are the ortho and para positions.
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.
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.
Why does NO2 group show its effect only at ortho and para positions and not at meta position of aryl halide during nucleophilic substitution?
The presence of the ortho- and para-position nitro group withdraws electron density from the benzene ring and thereby promotes the haloarene attack by the nucleophile. Hence, as we all discovered in organic chemistry, NO2 is a meta-director. …
Why does NO2 not show its effect at meta position?
Since NO2 is an electron withdrawing group, a glance at the resonance structures shows that the positive charge becomes concentrated at the ortho-para positions. Thus these positions are deactivated towards electrophilic aromatic substitution. Hence, NO2 is a meta-director, as we all learned in organic chemistry.
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.