Phenol $\xrightarrow[{{H^ + }}]{{CHCl_3/NaOH}}$ Salicylaldehyde. The above reaction is known as:

Which of the following statements is correct?

What is formed on heating an aqueous solution of benzene diazonium chloride?

In the given reaction sequence,identify the processes $X$ and $Y$ respectively to obtain salicylaldehyde from chlorobenzene:
$Chlorobenzene$ $\xrightarrow{X} Phenol$ $\xrightarrow{Y} Salicylaldehyde$

Which of the following is acidic?

Which product is obtained on treating phenol with concentrated $HNO_3$?