- Thấy Cu không phản ứng với HCl .
\(\Rightarrow m_{cr}=m_{Cu}=6,4\left(g\right)\)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
.x.......................................1,5x.........
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
.y....................................y.............
Theo bài ra ta có hệ : \(\left\{{}\begin{matrix}27x+56y+6,4=17,4\\1,5x+y=0,4\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\) ( mol )
\(\Rightarrow\left\{{}\begin{matrix}m_{Al}=5,4\\m_{Fe}=5,6\end{matrix}\right.\) ( g )
b, \(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_2+2NaCl\)
.......0,1.........0,2...............................
\(AlCl_3+3NaOH\rightarrow Al\left(OH\right)_3+3NaCl\)
...0,2.......0,6..........................
\(\Rightarrow n_{NaOH}=0,2+0,6=0,8< 1\)
=> Trong B còn có HCl dư .
\(NaOH+HCl\rightarrow NaCl+H_2O\)
...0,2..........0,2....................
=> Dư 0,2 mol HCl .
\(\Rightarrow n_{HCl}=2n_{H_2}+0,2=1\left(mol\right)\)
\(\Rightarrow m_{ddB}=17,4+250-6,4-0,8=260,2\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{HCl}=\dfrac{0,2.36,5}{260,2}.100\%\approx2,8\%\\C\%_{FeCl_2}\approx4,88\%\\C\%_{AlCl_3}\approx10,26\%\end{matrix}\right.\)
Vậy ....