Đáp án đúng: B HNO3 $\begin{array}{l}\text{F}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\text{+HN}{{\text{O}}_{\text{3}}}\xrightarrow{{}}\text{Fe(N}{{\text{O}}_{\text{3}}}{{\text{)}}_{\text{3}}}\text{+}{{\text{H}}_{\text{2}}}\text{O}\\\text{F}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}}\text{+10HN}{{\text{O}}_{\text{3}}}\xrightarrow{{}}\text{3Fe(N}{{\text{O}}_{\text{3}}}{{\text{)}}_{\text{3}}}\text{+N}{{\text{O}}_{\text{2}}}\text{+5}{{\text{H}}_{\text{2}}}\text{O}\end{array}$
