Salol is obtained from which of the following substances?

The reaction which involves dichlorocarbene as an electrophile is,

The correct order of decreasing acidity of nitrophenols is:

The correct order of $pK_{a}$ values for the following compounds is:
$(a)$ Phenol
$(b)$ $p$-Dimethylaminophenol
$(c)$ $p$-Nitrophenol
$(d)$ $p$-Isopropylphenol

Which of the following reactions is not an electrophilic substitution reaction?

One mole of phenol reacts with bromine to form $2,4,6-$tribromophenol. $X \ mol$ of bromine is used. The value of $X$ is: