I've used up my 4 out of 5 chances to get the answer on my online homework and really need help with this please.
Identify which reagent gets oxidized in each of the following redox reactions.

1. N2 or H2? N2+ 3H2 2NH3

2. CuCl2 or Ca? Ca + CuCl2 CaCl2 + Cu

3. NiS or O2? 3O2 + 2NiS 2NiO + 2SO2

4. H2SO3 or HNO3? 3H2SO3 + 2HNO3 2NO + H2O + 3H2SO4

View the original article here