Question

Which of the following reactions will yield phenol?

• A.
  $\underset{\left(ii\right)HCl}{\overset{\left(i\right)NaOH(aq.),298K/1atm}{\to }}$
• B.
  $\underset{\left(ii\right)NaOH\left(heating\right)\left(iii\right)H^{+}}{\overset{\left(i\right)Oleum}{\to }}$
• C.
  $\underset{\left(ii\right)H_{2}O\left(warming\right)}{\overset{\left(i\right)NaN{O}_2/HCl}{\to }}$
• D.
  $\underset{\left(ii\right)H_{2}O/H^{+}}{\overset{\left(i\right)fusionwithNaOHat300atm}{\to }}$

Answer 1

Answer: (B), (C), (D)

$\underset{\left(ii\right)H_{2}O/H^{+}}{\overset{\left(i\right)fusionwithNaOHat300atm}{\to }}$
$\text{Analysing the options}$

Option (A):
When Chlorobenzene is fused with $NaOH$ at $300$ atm followed by acidification, it results in the formation of Phenol.


Option (B)
When Aniline is treated with $NaN{O}_2+HCl$, a diazonium salt is formed. When diazonium salt is hydrolysed by warming with water, it gives phenol.


Option (C)
Benzene is sulphonated with oleum and benzenesulfonic acid is formed. Benzenesulfonic acid is converted to phenol by treating it with molten sodium hydroxide followed by acidification.


Option (D)
Option $\left(D\right)$ is incorrect because reaction conditions given to convert chlorobenzene to phenol are very mild and not suitable for this conversion.

So, the correct answers are options $\left(A\right),\left(B\right)$ and $\left(C\right)$.