Phenol on heating with `NaNO_(2)` and a few drops of conc. `H_(2) SO_(4)` gives :

Catechol on heating with phthalic anhydridee in the presence of conc. H_(2)SO_(4) gives :

Anisole with conc. H_(2)SO_(4) gives.

A compound 'X' on heating with phthalic anhydride and a few drops of conc: H_(2)SO_(4) , produced a colourless substance, which gave a pink colour on adding NaOH solution. The compound 'X' is

Phthalic anhydride on heating with resorcinol in the presence of conc. H_(2)SO_(4) gives :

Phthalic anhydride on heating with resorcinol in the presence of conc. H_(2)SO_(4) gives :

KMnO_(4) is heated with conc. H_(2)SO_(4) gives

Glycerol when heated with conc. H_(2)SO_(4) gives