Which of the following is the strongest Bronsted acid?

The reactant is $4-hydroxy-3-methylbenzenesulfonic acid$. The reaction with $Br_2$ in $H_2O$ (bromine water) is an electrophilic aromatic substitution. The $-OH$ group is strongly activating and ortho/para directing. The $-SO_3H$ group is a good leaving group in the presence of excess bromine water. Predict the product of the reaction: $\xrightarrow{Br_2, H_2O} \text{Product}$

The ionisation constant of phenol is higher than that of ethanol because

The common name of $Benzene-1,4-diol$ is

The compound that is most difficult to protonate is

The product obtained is/are