Explain why the alkoxy $(-OR)$ group is an ortho-para directing and ring-activating group for electrophilic aromatic substitution reactions.

(N/A) The $-OR$ group is activating: The alkoxy $(-OR)$ group donates its lone pair of electrons to the benzene ring through resonance. As a result,the electron density in the ring increases,making the ring electron-rich. This facilitates electrophilic substitution in the ring. Thus,the $(-OR)$ group activates the benzene ring.
$(b)$ The alkoxy group is ortho-para directing:
$(i)$ The resonance structures of alkoxybenzene are shown below.
$(ii)$ In the resonance structures,the electron density (negative charge) is increased at the ortho and para positions,making these carbons electron-rich.
$(iii)$ Consequently,electrophilic reagents are attracted to and attack at the ortho and para positions.
Thus,the alkoxy group is an ortho-para directing group for electrophilic substitution reactions.