why do nitro compounds dissolve in sodium hydroxide?
The compounds containing nitro groups when dissolved in basic medium, the following things can happen. The base can take the α-Hα-H of the nitro-group, which will create a negative charge on that α-Cα-C, which can further delocalise with the Nitro-group (similar to Nitro-Acinitro tautomerism). So, the whole compound will be in the state of a Resonance Hybrid where there will be partial double bond character between α-C,Nα-C,N and two OO atoms. and also there will be a δδ- charge on the α-Cα-Catom as well as on the OO atoms. , and δδ+ charge on the NN atoms.Due to such salt like compound formation, it becomes soluble. This δδ- charge created on the Carbon atom is stable if the side chain is short, but starts to get destabilised as the side chain grows longer. So, I think the solubilities of the Nitro-compounds decrease as the side chain grows longer, and the compound with 10−1210−12 C atoms may not be at all soluble in base because of such large Hydrophobic part and destabilisation of the δδ- charge.