Nhúng lá sắt vào 150 ml dung dịch chứa CuCl2 1M

Ban đầu: $n_{CuC{l}_2}=\mathrm{0,15}$và $n_{HCl}=\mathrm{0,3}$

$\begin{array}{l}Fe+C{u}^{2+}\to F{e}^{2+}+Cu\\ x\mathrm{.............................}x\\ Fe+2H^{+}\to F{e}^{2+}+H_2\\ \mathrm{0,1.........................0,1}\end{array}$

$\begin{array}{l}\Delta m=64x-56(x+\mathrm{0,1})=-\mathrm{5,2}\\ \to x=\mathrm{0,05}\end{array}$

Dung dịch X chứa $F{e}^{2+}\left(\mathrm{0,15}\right);C{u}^{2+}\left(\mathrm{0,1}\right);C{l}^{-}\left(\mathrm{0,6}\right)$ và $H^{+}$dư (0,1)

Thêm vào X một lượng $n_{NaN{O}_3}=\mathrm{0,025}$

$\begin{array}{l}3F{e}^{2+}+4H^{+}+N{O}_3^{-}\to 3F{e}^{3+}+NO+2H_{2}O\\ \mathrm{0,15.....0,1.....0,025}\\ \mathrm{0,075...0,1.....0,025}\\ \mathrm{0,075....0........0}\end{array}$

m muối = $m_{Na}+m_{Fe}+m_{C{u}^{2+}}+m_{C{l}^{-}}=\mathrm{36,675}$