Table of Contents
- 1 Why is OH more activating than OCH3?
- 2 Why hydroxyl group is ortho and para directing?
- 3 Which has more Mesomeric effect OH or OR?
- 4 Why OH has more +M effect than OR?
- 5 Why is phenyl ortho para directing?
- 6 Is Oh op directing group?
- 7 What is the difference between ortho para and meta directing groups?
- 8 Which is more electron donating group -OCH3 or -CH3?
Why is OH more activating than OCH3?
OH (hydroxy) has a better +R effect than OCH3 because The -CH3 group in -OCH3 causes steric repulsions with lone pairs, increasing bond angles. Due to which it make -O- atom of -OCH3 more electro-negative and thus affecting donor tendency.
Which has more +M effect OH or OCH3?
OCH3 group is more electron withdrawing (i.e, shows more -I effect) than the OH group. Explanation: The reason is that, there are two lone pairs of oxygen. Oxygen has a smaller size, so in case of OCH3, the methyl group is close to the lone pair electrons, which leads to Steric repulsion.
Why hydroxyl group is ortho and para directing?
The group which increases the electron density at ortho and para positions are called as ortho-para directors, Example: -OH. h is quite evident that the lone pair of electrons on the atom which is attached lo the ring is involved in resonance and it makes the ring more electron rich than benzene.
Is OH an ortho or para director?
| Electronic Effect | Examples | Direction |
|---|---|---|
| donation – conjugation | -NH2, -OH | ortho, para |
| donation – inductive effect | -Alkyl | ortho, para with some meta |
| donation – conjugation, withdrawal – inductive effect | -F, -Cl, -Br, -I | ortho and (mostly) para |
| withdrawal – inductive effect | -CF3 | meta |
Which has more Mesomeric effect OH or OR?
+M effect of OH greater than OCH3 Explanation:- The -R group in -OR causes steric repultions with lone pairs, increasing bond angles. +R effect of OCH3 is more than that of OH group. +R effect: The groups show positive mesomeric effect when they release electrons to the rest of the molecule by delocalization.
What is the effect of ortho and para directing group on orientation?
Ortho and para attack produces a resonance structure which places the arenium cation next to and additional cation. This destabilizes the arenium cation and slows down ortho and para reaction. By default the meta product forms faster because it lacks this destablizing resonance structure.
Why OH has more +M effect than OR?
In some books it is written that +M (mesomeric effect) effect of OH is less than that of OR . The reason they give is inductive effect of R (group) which sounds senseful . But at some places it is written +M of OR is less (which is correct).
Why or has more i effect than OH?
-OR have more -I effect than -OH. The main cause of -I effect is electronegativity differernce. Electronegativity difference in O and C is 1.0 and electronegativity difference between O and H is 1.5.
Why is phenyl ortho para directing?
Phenol is an ortho/para director, but in a presence of base, the reaction is more rapid. It is due to the higher reactivity of phenolate anion. The negative oxygen was ‘forced’ to give electron density to the carbons (because it has a negative charge, it has an extra +I effect).
Is OCH3 ortho para directing?
Both –OCH3 and –Ph are activating, ortho-/para-directing groups.
Is Oh op directing group?
since OH is +R/+M group thus provides e- to the benzene ring thus creates +ve charge on meta position and -ve charge on ortho and para position thus it is ortho para directing group…
Why does Oh have a better +R effect than OCH3?
OCH3 or OH and why? OH (hydroxy) has a better +R effect than OCH3 because The -CH3 group in -OCH3 causes steric repulsions with lone pairs, increasing bond angles. Due to which it make -O- atom of -OCH3 more electro-negative and thus affecting donor tendency.
What is the difference between ortho para and meta directing groups?
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.
What is the difference between -OCH3 and -CH3?
In these two groups, -CH3 gives a +I effect whereas -OCH3 gives a strong -I effect. The electronegativity of oxygen in -OCH3 dominates over the +I of-CH3 and thus the overall group gives a negative inductive effect.
Which is more electron donating group -OCH3 or -CH3?
Due to +R effect of -OCH3 group which arises due to the lone pair of oxygen atom,it become more electron donating group than -CH3 group where only +Ieffect is present. Always Resonence effect is stronger than Inductive effect except for halogen atom.