The nature of $2,4,6-$trinitrophenol is

The major product in the following reaction is:

An organic compound $C_6H_7N$ on reaction with $NaNO_2 / HCl$ at $273-278 \ K$ followed by warming with water gives $B$. $B$ reacts with concentrated $HNO_3$ to give $C$. What is $C$?

Explain why $ortho$-nitrophenol is more acidic than $ortho$-methoxyphenol?

The increasing order of acidic strength of the given compounds is:

The major product of the following reaction sequence is