Analyze Assertion A

Assertion A: Aryl halides cannot be prepared by replacement of hydroxyl group of phenol by halogen atom.

This statement is true.

Reason: In phenol, the C–O bond has partial double bond character due to resonance between the lone pair on oxygen and the aromatic ring:

$\text{Ar–OH} \leftrightarrow \text{resonance structures}$

Because of this, the aryl C–O bond is stronger and cannot be easily cleaved by reagents such as $\mathrm{HX}$, $\mathrm{PCl_5}$, or $\mathrm{SOCl_2}$, unlike alcohols. Hence, phenol does not readily give aryl halides by direct replacement of $-OH$.

Analyze Reason R

Reason R: Phenols react with halogen acids violently.

This statement is false.

In fact, phenols do not react with halogen acids like $\mathrm{HCl}$, $\mathrm{HBr}$, or $\mathrm{HI}$ to form aryl halides under ordinary conditions. So saying they react violently is incorrect.

Match with the options

• A is true
• R is false

Therefore, the correct option is:

$\boxed{\text{A}}$

Compare with stored correct answer

Stored correct answer = A

Our derived answer = A

So, they agree.