Đáp án đúng: D
32 gam.
$\displaystyle \begin{array}{l}\text{3FeC}{{\text{O}}_{\text{3}}}\text{+ 10 HN}{{\text{O}}_{\text{3}}}\xrightarrow{{}}\text{3Fe}{{\left( \text{N}{{\text{O}}_{\text{3}}} \right)}_{\text{3}}}\text{+ NO + 3C}{{\text{O}}_{\text{2}}}\text{+ 5}{{\text{H}}_{\text{2}}}\text{O}\\\text{ }\!\!~\!\!\text{ }\,\,\,\,\,\text{0,1 }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ }\,\,\,\,\,\,\xrightarrow{{}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\text{ }\!\!~\!\!\text{ 0,1 }\!\!~\!\!\text{ }\!\!~\!\!\text{ (mol)}\end{array}$
$\displaystyle {{\text{n}}_{\text{(NO}_{\text{3}}^{\text{-}}\text{)}}}\text{= 0,3 mol}$
$\displaystyle \begin{array}{l}\text{3Cu + 8}{{\text{H}}^{\text{+}}}\text{ + 2N}{{\text{O}}_{\text{3}}}\xrightarrow{{}}\text{ 3C}{{\text{u}}^{\text{2+}}}\text{+2NO+4 }{{\text{H}}_{\text{2}}}\text{O}\\\text{0,45}\,\,\,\,\,\,\,\,\xleftarrow{{}}\,\,\,\,\,\,\,\,\,\,\,\,\text{0,3}\end{array}$
$\displaystyle \begin{array}{l}\text{Cu }\!\!~\!\!\text{ + 2Fe}{{\left( \text{N}{{\text{O}}_{\text{3}}} \right)}_{\text{3}}}\xrightarrow{{}}\text{ Cu}{{\left( \text{N}{{\text{O}}_{\text{3}}} \right)}_{\text{2}}}\text{+ 2 Fe}{{\left( \text{N}{{\text{O}}_{\text{3}}} \right)}_{\text{2}}}\\\text{0,05}\,\,\leftarrow \,\,\text{0,1}\end{array}$
$\displaystyle \Rightarrow \text{ }{{\text{m}}_{\text{Cu}}}\text{ = }\left( \text{0,05+0,45} \right)\text{.64 =32 g }\!\!~\!\!\text{ }~$
