Which of the following is the weakest acid?

The major reason that phenol is a better Bronsted acid than cyclohexanol is that

Heating phthalic anhydride and concentrated sulfuric acid with which of the following yields phenolphthalein?

The reaction of phenol with chloroform in the presence of dilute sodium hydroxide introduces which one of the following functional groups?

Consider the following reaction:
The product $'P'$ gives a positive ceric ammonium nitrate test. This is because of the presence of which of these $-OH$ group$(s)$?

Which of the following compounds reacts with ethylmagnesium bromide and also decolourizes bromine water solution?