Question

The group which is predominantly ortho/para directing when attached to a benzene ring is :

• A. $-OH$
• B. $-N{O}_2$
• C. $-CN$
• D. $-CHO$

Answer 1

The correct option is A $-OH$

From the resonance structures of alcohol, we can see that the electron density at ortho and para positions will be higher than the electron density at meta position. That means $-OH$ is an ortho-para directing group towards an electrophile (electron loving species).
Hence, electrophilic substitution reaction in phenol takes place at ortho and para position.


$-N{O}_2,-CN,-CHO$ show -R effect and are meta directing.