Răspuns:
1. S+2HNO3 => 2NO +H2SO4
S⁰- 6e=> S⁶ oxidare agent redactor
N⁵+3e=>N²reducere agent reducator×2
S⁰- 6e=> S⁶
2N⁵+ 6e=> 2N²
2.
3P +5HNO3 + 2H2O=5NO + 3H3PO4
P⁰+5e=>P⁵ oxidare agent redactor ×3
N⁵-3e=>N² reducere agent oxidant ×5
3P⁰- 15e=>3P⁵
5N⁵ + 15e=> 5N²⁶