An organic compound A C 6 H 7 N on reaction with NaNO 2 / HCl at 273 - 278   K followed by warming with…

${\mathrm{C}}_6{\mathrm{H}}_7\mathrm{N}$ corresponds to aniline (A). Aniline undergoes diazotisation reaction to give diazonium salt which on hydrolysis produces phenol (B). With concentrated nitric acid, phenol is converted to $2,4,6$-trinitrophenol (C). The product is commonly known as picric acid.