\(n_{H_2}=\dfrac{12,395}{24,79}=0,5\left(mol\right)\)
PTHH:
\(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
x 2x x x
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
y 2y y y
\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
z 2z z z
\(ZnCl_2+2NaOH\rightarrow2NaCl+Zn\left(OH\right)_2\downarrow\)
x 2x 2x x
\(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_2\downarrow+2NaCl\)
y 2y y 2y
\(MgCl_2+2NaOH\rightarrow Mg\left(OH\right)_2\downarrow+2NaCl\)
z 2z z 2z
\(Zn\left(OH\right)_2\rightarrow\left(t^o\right)ZnO+H_2O\)
x x x
\(4Fe\left(OH\right)_2+O_2\rightarrow\left(t^o\right)2Fe_2O_3+4H_2O\)
y 0,5y y
\(Mg\left(OH\right)_2\rightarrow\left(t^o\right)MgO+H_2O\)
z z z
Ta có Hệ PT:
\(\left\{{}\begin{matrix}x+y+z=0,5\\65x+56y+24z=20,9\\81x+80y+40z=22\end{matrix}\right.\)
Bạn check lại đề có sai ở đâu k nha chứ bậm nghiệm k ra.