Question

Which of the following statements are correct?
(This question has multiple correct options)
A.An activating group is an electron-releasing group.
B.An activating group activates all positions of the benzene ring
C.The effect of any group – whether activating or deactivating – is the strongest at the ortho- and para- positions in the benzene ring
D.An activating group activates only the ortho-and para-positions in the benzene ring

Answer 1

Hint: Activating group is electron donating group because they increase the rate of the second substitution so that it is higher than that of standard benzene whereas Deactivating group is electron accepting group and they deactivate the ring by the inductive effect in the presence of an electronegative atom.

Complete step by step answer:
Substitute rings are basically divided into two groups based on the basis of the substituent that the ring has or it carries. These group are:
1) Activating rings
2) deactivating rings
1) Activating Rings- These rings are formed by activating groups and activating groups increases the rate of reaction, relative to H. Activating group relatively tends to give or donate electron density to the ring, that is it is an electron releasing group. And thus, this group activates all the positions of the benzene ring.
2) Deactivating Rings- These rings are formed by deactivating groups and deactivating groups decreases the rate of reaction, relative to H. Deactivating group relatively tends to take back or withdraw electron density from the ring.
These donation and withdrawal can cause by two effects namely, inductive effect or via donation and withdrawal of the lone pair which is also known as sigma donation/accepting and the other is known as pi donation/accepting.
When the substituents like \[ - OH\] have the pair of electrons is unshared or lone pair of electrons then the resonating effect is stronger than the inductive effect which will ultimately make these substituent group a strong activator as these effects, the resonating effect force the electron towards the rings. Halogens are an exception of the deactivating group which is directed towards ortho and para position. Halogen deactivate the ring by inductive effect and not by the resonating effect even if they have unpaired or lone pair electrons.

Therefore, the correct answers are option (A), (B) and (C).

Note: The effect of a group is strongest at the ortho or para position in the benzene ring even if they are an activating group or deactivating group. Substitutes like ester or amides are less activating.