The reagent among the following that does not reduce an aryl nitro compound to an amine is:
1. H2(excess) / Pt
2. LiAlH4 in ether
3. Fe and HCI
4. Sn and HCI
In nitration of benzene using a mixture of conc. H2SO4 and conc. HNO3, the species that initiates the reaction is :
1. NO2
2. NO+
3. NO2+
4. NO2-