Question

Assertion (A): Phenol, on treatment with Br₂ in CS₂, gives ortho and para products.

Reason (R): Carbon disulphide is a solvent of low polarity, hence leads to monobromination of phenols.
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, but R is not the correct explanation of A.
c) A is true, but R is false.
d) A is false, but R is true.

Answer 1

The assertion regarding the reaction of phenol with bromine in carbon disulfide yielding ortho and para products is correct due to the directing effect of the -OH group on the phenol.

Step-by-step explanation:

When phenol (C6H5OH) is treated with bromine (Br2) in carbon disulfide (CS2), it undergoes an electrophilic aromatic substitution reaction that typically yields ortho and para substituted products. This is because the -OH group on the phenol ring is an activating group that directs the electrophilic Br2 to the ortho and para positions due to resonance stabilization of the intermediates formed during the reaction. Therefore, the assertion that phenol, when treated with Br2 in CS2, gives ortho and para products is indeed correct.

Moreover, the unique character of phenol's -OH group distinguishes it significantly from alcohols; phenol exhibits a slight acidity due to its ability to lose a hydrogen ion, which is not characteristic of typical alcohols. However, the reaction with Br2 in CS2 is not directly related to this acidic property, but rather to the electron-rich nature of phenol that leads to the ortho and para substitution pattern.