Đáp án đúng: B
0,60.
$\displaystyle \begin{array}{l}\text{CuC}{{\text{l}}_{\text{2}}}\,\,\,\,\,\,\,\,\xrightarrow{\text{dpdd}}\text{ Cu}\,\,\,\,\,\text{ + }\,\,\,\text{C}{{\text{l}}_{\text{2}}}\\0,075<----1,68/22,4\text{ }=\text{ }0,075\end{array}$
dung dịch X : CuCl2 còn dư
$\displaystyle \begin{array}{l}\,\,\,\,\,\,\,\,\,\,\,\,\text{Fe }\!\!~~~~~\!\!\text{ }\!\!~\!\!\text{ }\,\,\,\,\,\,\,\,\,\text{+ }\!\!~\!\!\text{ }\,\,\,\,\,\,\,\,\,\text{CuC}{{\text{l}}_{\text{2}}}\text{ }\!\!~\!\!\text{ }\,\,\,\,\xrightarrow{{}}\,\,\,\,\,\,\,\text{FeC}{{\text{l}}_{\text{2}}}\text{ }\!\!~\!\!\text{ }\,\,\,\,\text{+ }\,\,\,\,\text{ Cu}\\\text{12,6/56=0,025}\,\,\,\to \,\,\,\text{0,225}\end{array}$
$\displaystyle {{\text{n}}_{\text{CuC}{{\text{l}}_{\text{2}}}}}\text{ }\!\!~\!\!\text{ }\!\!~\!\!\text{ = 0,075 + 0,225 = 0,3}\left( \text{mol} \right)\text{ }\Rightarrow \text{ V = 0,3/0,5 = 0,6}~$
