The major product in the following reaction is:

Which among the following compounds has the highest melting point?

What is the product formed when phenol reacts with concentrated $HNO_3$?

Which of the following is the most acidic compound?

Arrange the following compounds in increasing order of their acid strength: $Propan-1-ol$,$2,4,6-trinitrophenol$,$3-nitrophenol$,$3,5-dinitrophenol$,$phenol$,$4-methylphenol$.

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.