- Phản ứng: $\underbrace{F{{e}_{2}}{{O}_{3}},\,Cu}_{\text{hn h }\!\!\hat{\mathrm{i}}\!\!\text{ p}}\xrightarrow{{{H}_{2}}S{{O}_{4}}\text{(d)}}\underbrace{F{{e}^{2+}},\,C{{u}^{2+}},\,{{H}^{+}}_{(d)},\,S{{O}_{4}}^{2-}}_{dung\text{ dch X}}+Cu\ (\text{r }\!\!{\scriptscriptstyle 3\!/\!{ }_4}\!\!\text{ n kh }\!\!\ll\!\!\text{ ng tan)}$ .

- Dung dịch X tác dụng được với $$ chất sau:

     $Fe+CuS{{O}_{4}}\xrightarrow{{}}Cu+FeS{{O}_{4}}\text{ }\ \text{v }\!\!\mu\!\!\text{  }\ \text{Fe + }{{\text{H}}_{2}}S{{O}_{4}}\xrightarrow{{}}FeS{{O}_{4}}+{{H}_{2}}$

     $3F{{e}^{2+}}+N{{O}_{3}}^{-}+4{{H}^{+}}\xrightarrow{{}}3F{{e}^{3+}}+NO+2{{H}_{2}}O$

$6FeS{{O}_{4}}+3C{{l}_{2}}\xrightarrow{{}}2F{{e}_{2}}{{(S{{O}_{4}})}_{3}}+2FeC{{l}_{3}}$

$10FeS{{O}_{4}}+2KMn{{O}_{4}}+8{{H}_{2}}S{{O}_{4}}\xrightarrow{{}}5F{{e}_{2}}{{(S{{O}_{4}})}_{3}}+{{K}_{2}}S{{O}_{4}}+2MnS{{O}_{4}}+8{{H}_{2}}O$