What is the product formed when salicylic acid is treated with zinc dust?

While separating a mixture of $o-$ and $p-$nitrophenols by steam distillation,name the isomer which will be steam volatile. Give reason.

Identify the final product obtained when a mixture of vapours of phenol and hydrogen is passed over nickel catalyst at $433 \ K$.

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 $C$?

The compound that is most difficult to protonate is

Identify the product obtained when phenol reacts with concentrated sulphuric acid at $293 \ K$?