Arrange the following compounds in the correct order of their acid strength.

Phenol is:

Which one of the following compounds gives aspirin on reacting with acetic anhydride in the presence of conc. $H_2SO_4$?

Write the structures of the major products expected from the following reactions:
$(a)$ Mononitration of $3-$methylphenol
$(b)$ Dinitration of $3-$methylphenol
$(c)$ Mononitration of phenyl methanoate.

Two aromatic compounds having formula $C_7H_8O$ which are easily identifiable by $FeCl_3$ solution test (violet colouration) are

Some compounds and their $pK_a$ values are given. Arrange them in decreasing order of their acidic strength.
$(i)$ Ethanol $(15.9)$,Phenol $(10.0)$,Cresol $(10.1)$,Water $(15.7)$
$(ii)$ $o$-Nitrophenol $(7.2)$,$m$-Nitrophenol $(8.3)$,Ethanol $(15.9)$,Water $(15.7)$,Phenol $(10.0)$