Đáp án đúng: A
Giải chi tiết:\(\begin{gathered} X:\left. {\left\{ \begin{gathered} Mg:\,a\,mol \hfill \\ Cu{(NO_3^{})_2}:0,25\,mol \hfill \\ \end{gathered} \right.} \right\}\xrightarrow{{nung}}Y + \,\underbrace {N{O_2}\,va\,{O_2}}_{0,45\,mol} \hfill \\ Y\xrightarrow{{1,3\,mol\,HCl}}m\,(gam)\,\left. {\left\{ \begin{gathered} M{g^{2 + }}:\,a\,mol \hfill \\ C{u^{2 + \,}}:0,25 \hfill \\ N{H_4}^ + :b\,mol \hfill \\ C{l^ - }\,:1,3\,mol \hfill \\ \end{gathered} \right.} \right\} + 0,05\,mol\,Z\left\{ \begin{gathered} {N_2}:\,0,04 \hfill \\ {H_2}:0,02 \hfill \\ \overline M z = 22,8 \hfill \\ \end{gathered} \right. + {H_2}O:y\,mol \hfill \\ \left\{ \begin{gathered} \xrightarrow{{BTNT\,:\,\,\,O}}0,25.6\, = 0,45.2 + \,y \hfill \\ \xrightarrow{{BTNT:\,\,\,H}}1,3 = 4b\, + 0,01.2 + \,2y \hfill \\ \end{gathered} \right. = > \left\{ \begin{gathered} y = \,0,6 \hfill \\ b = 0,02 \hfill \\ \end{gathered} \right. \hfill \\ \hfill \\ \end{gathered} \)
Bảo toàn điện tích đối với hỗn hợp muối clorua ta có:
2a+ 0,25.2 + 0,02.1 = 1,3 =>a = 0,39
=> m = 0,39. 24 +0,25.64 + 0,02.18 + 1,3.35,5 = 71,87 (g) ≈ 72(gam)
Đáp án A
