Infact,
\(A c i d+N a H C O_{3} \longrightarrow S a l t+H_{2} C O_{3}\)
This reaction is possible in forward direction if acid is more acidic than \(H_{2} C O_{3}\) o-nitrophenol is less acidic than \(H_{2} C O_{3} .\) Hence, it is not soluble in sodium hydrogen carbonate.
$[Figure]$ $\xrightarrow{{HBr}}$
$[Figure]$ $\xrightarrow[{2.\,C{H_3}I\,(l.\,eq.)}]{{1.\,{K_2}C{O_3}}}$