Question

Why -OH group is ortho and para directing in nature?

Answer 1

when we attach OH group to benzene it shows electron density is higher at ortho and para positions so it is ortho para directing group. we can find electron density by resonating structure.

Answer 2

Ortho/para directing in group have most negative charges on the ortho/para position,while meta directing groups often possess the largest negative charge on the meta posirion