Question

Which of the following groups will increase the acidity of phenol?

• A. $-N{O}_2$
• B. $-CN$
• C. $-X$ (halogen)
• D. None of these

Answer 1

Answer: (A), (B), (C)

The correct options are
A $-N{O}_2$
B $-CN$
C $-X$ (halogen)

$-N{O}_2$, $-CN$ and $-X$ (halogen) groups will increase the acidity of phenol. These are electron withdrawing groups and stabilize the negative charge of phenoxide ion. Due to this, the removal of proton becomes easy.