Đáp án đúng: B
Giải chi tiết:\(\begin{gathered} {n_{{H^ + }}} = {n_{HCl}} + {n_{HN{O_3}}} = 0,5.2,4 + 0,5.0,2 = 1,3mol \hfill \\ {n_{N{O_3}^ - }} = {n_{HN{O_3}}} = 0,1;n(C{l^ - }) = 1,2{\text{ }} \hfill \\ \end{gathered} \)
Nung kết tủa trong không khí đến khối lượng không đổi thu được chất rắn Z gồm Fe2O3 và CuO.
Gọi số mol Fe3O4 và Cu lần lượt là x, y ( x,y >0)
Ta có hệ phương trình:
\(\begin{gathered} \left\{ \begin{gathered} {m_{F{e_3}{O_4}}} + {m_{Cu}} = 37,28 \hfill \\ {m_{F{e_2}{O_3}}} + {m_{CuO}} = 41,6 \hfill \\ \end{gathered} \right. \to \left\{ \begin{gathered} 232x{\text{ }} + {\text{ }}64y{\text{ }} = {\text{ }}37,28 \hfill \\ 1,5x.160{\text{ }} + {\text{ }}80y{\text{ }} = {\text{ }}41,6 \hfill \\ \end{gathered} \right. \to x = 0,1;y = 0,22 \hfill \\ 3F{e_3}{O_4} + 28{H^ + } + N{O_3}^ - \to 9F{e^{3 + }} + NO + 14{H_2}O(1) \hfill \\ 0,1 \to {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} 2,8/3{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,3\,\,\,\,\,\,\,\,\,0,1/3{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \hfill \\ 3Cu + 8{H^ + } + 2N{O_3}^ - \to 3C{u^{2 + }} + 2NO + 4{H_2}O{\mkern 1mu} {\mkern 1mu} (2) \hfill \\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,1{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,\,\,\,\,\,\,\,\,\,\,\,\,\,4/15{\mkern 1mu} \, \leftarrow 0,2/3 \hfill \\ Cu + {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} 2F{e^{3 + }} \to 2F{e^{2 + }} + C{u^{2 + }}{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} (3) \hfill \\ 0,12 \to 0,24{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} 0,24{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,\,\,\,\,{\mkern 1mu} 0,12 \hfill \\ \end{gathered} \)
Dung dịch Y sau phản ứng chứa 0,22 mol Cu2+; 0,24 mol Fe2+; 0,06 mol H+ dư, 1,2 mol Cl-.
Khi Cho AgNO3 vào dung dịch Y xảy ra các phản ứng:
\(\begin{gathered} A{g^ + } + C{l^ - } \to AgCl\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3F{e^{2 + }} + \,\,\,\,4{H^ + } + N{O_3}^ - \to 3F{e^{3 + }} + NO + 2{H_2}O \hfill \\ \,\,\,\,\,\,\,\,\,\,\,\,1,2\,\,\,\,\,\,\,\,\,\,\,\,\,1,2\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,075 \leftarrow 0,1 \hfill \\ F{e^{2 + }} + A{g^ + } \to F{e^{3 + }} + Ag \hfill \\ 0,165\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,165 \hfill \\ \Rightarrow m = {m_{AgCl}} + {m_{Ag}} = 1,2.143,5 + 0,165.108 = 190,02gam \hfill \\ \end{gathered} \)
Đáp án B
