Statement 1 Phenol gives p-bromophenol as the major product when treated \(\mathrm{Br}_{2}\) dissolved in carbon disulphide at low temperature. and Statement 2 p-Bromophenol has lower \(\mathrm{pK}_{\text {a }}\) value than phenol.

The reaction of phenol with bromine dissolved in carbon disulphide at low temperature follows an electrophilic substitution mechanism. Bromine acts as an electrophile, attacking the benzene ring in the phenol molecule. As a result, one of the hydrogen atoms in the benzene ring is replaced by a bromine atom to form bromophenol.

The oxygen atom in the hydroxyl group (-OH) of phenol has a pair of electrons that can be donated to the benzene ring. This donation helps to stabilize the intermediate formed during the reaction by dispersing the positive charge through resonance structures. This means that the electrophile (bromine) is more likely to attack the carbon atoms ortho to (next to) or para to (opposite) the hydroxyl group. Both ortho-bromophenol and para-bromophenol result from these two possible attack sites.

Due to steric hindrance, the para-bromophenol is formed as the major product in this reaction. Steric hindrance occurs because of the presence of bulky groups in a molecule, which hinder the approach of other species. In this case, the hydroxyl group (-OH) of phenol creates steric hindrance for the ortho-position, making the approach of the electrophile (bromine) less favorable. Therefore, the attack at the para-position is more favorable, leading to the formation of para-bromophenol (p-bromophenol) as the major product.

To compare the acidity of phenol and p-bromophenol, we need to compare their pKa values. The pKa value is a measure of the acidity of a substance; a lower pKa value indicates a stronger acid. Acidity is related to the ease with which a molecule can donate a proton (H+). The stability of the anion formed after proton donation plays a significant role in determining the acidity of a molecule.

When phenol loses a proton, it forms a phenoxide anion, which is resonance-stabilized due to the presence of the oxygen atom with negative charge delocalized over the benzene ring. In the case of p-bromophenol, after losing a proton, the bromine atom being an electron-withdrawing group further stabilizes the resulting anion by inductively withdrawing electron density from the already negative ion. This stabilization increases the ease with which p-bromophenol donates its proton, making it a stronger acid than phenol. Consequently, p-bromophenol has a lower pKa value than phenol. With these explanations, we can understand why the given statements are true. The reaction of phenol with bromine forms p-bromophenol as the major product due to the electrophilic substitution mechanism and steric hindrance effects. The pKa value of p-bromophenol is lower than that of phenol because the bromine atom stabilizes the anion formed after deprotonation, making it a stronger acid.