Đáp án đúng: A
27,965.
– Quá trình: $\overbrace{\ {Al}\ }^{{0,09}\ {mol}}{,}\overbrace{{F}{{{e}}_{{3}}}{{{O}}_{{4}}}}^{{0,04}\ {mol}}\xrightarrow{{{{t}}^{{o}}}}{hh}\ {X+HCl}\xrightarrow[{}]{}\underbrace{{AlC}{{{l}}_{{3}}}{,FeC}{{{l}}_{{2}}}{,FeC}{{{l}}_{{3}}}}_{{ dd sau pu}}{+}{{{H}}_{{2}}}{O+}\overbrace{\ {{{H}}_{{2}}}\ }^{{0,105}\ {mol}}$
+ Ta có:${{n}_{O\ (F{{e}_{3}}{{O}_{4}})}}={{n}_{{{H}_{2}}O}}=0,16\ mol$$\xrightarrow{BT:\ H}{{n}_{HCl}}=2({{n}_{{{H}_{2}}}}+{{n}_{{{H}_{2}}O}})=0,53\ mol$
– Hướng tư duy 1:
$\begin{array}{l}\xrightarrow{BTKL}a={{m}_{Y}}+36,{{5}_{HCl}}-2{{n}_{{{H}_{2}}}}-18{{n}_{{{H}_{2}}O}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,={{m}_{X}}+36,{{5}_{HCl}}-2{{n}_{{{H}_{2}}}}-18{{n}_{{{H}_{2}}O}}=27,965\,gam\end{array}$
– Hướng tư duy 2:
+ Ta có:$a={{m}_{KL}}+35,5{{n}_{C{{l}^{-}}}}=27{{n}_{Al}}+56{{n}_{Fe}}+35,5{{n}_{HCl}}=27,965\,gam$
