24.HNO3+P →H3PO4+NO2↑+H2O
x1 ${P^{0}}$→${P^{+5}}$ +5e
x5 ${N^{+5}}$+1e→${N^{+4}}$
⇒P+5HNO3→H3PO4+5NO2↑+H2O
25.Fe3O4+HNO3→Fe(NO3)3+NO↑+H2O
x3 3${Fe^{\frac{8}{3}}}$→3${Fe^{+3}}$+1e
x1 ${N^{+5}}$+3e→${N^{+2}}$
⇒3Fe3O4+28HNO3→9Fe(NO3)3+NO↑+14H2O
26.HNO3+P+H2O→H3PO4+N2O↑
x8 ${P^{0}}$→${P^{+5}}$ +5e
x5 2${N^{+5}}$+8e→2${N^{+1}}$
⇒8P+10HNO3+7H2O→8H3PO4+5N2O↑
-----------------------Nguyễn Hoạt----------------------