I need some help with understanding reducing agent selectivity. I recently did a lab where we used two reducing agents (separately) for 3-nitroacetophenone (benzene with a ketone group on an ethyl branch and a nitro group) sodium borohydride and tin in HCl. I know that sodium borohydride can only reduce carbonyl groups due to the mechanism, but I don't understand why tin in HCl would reduce the nitro group over the carbonyl group. Any help would be greatly appreciated /e on second thought I actually can't figure out why BH4+ can only reduce carbonyl. Please help!