a) \(\left\{{}\begin{matrix}56.n_{Fe}+27.n_{Al}=16,4\\n_{Fe}:n_{Al}=1:4\end{matrix}\right.\) => \(\left\{{}\begin{matrix}n_{Fe}=0,1\left(mol\right)\\n_{Al}=0,4\left(mol\right)\end{matrix}\right.\)
PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
0,1---->0,2------>0,1--->0,1
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0,4--->1,2------->0,4--->0,6
\(V_{H_2}=\left(0,1+0,6\right).22,4=15,68\left(l\right)\)
nHCl(pư) = 0,2 + 1,2 = 1,4 (mol)
=> \(n_{HCl\left(TT\right)}=\dfrac{1,4.110}{100}=1,54\left(mol\right)\)
=> \(x\%=\dfrac{1,54.36,5}{500}.100\%=11,242\%\)
b) mdd sau pư = 16,4 + 500 - 0,7.2 = 515 (g)
\(\left\{{}\begin{matrix}C\%_{FeCl_2}=\dfrac{0,1.127}{515}.100\%=2,466\%\\C\%_{AlCl_3}=\dfrac{0,4.133,5}{515}.100\%=10,369\%\\C\%_{HCl\left(dư\right)}=\dfrac{\left(1,54-1,4\right).36,5}{515}.100\%=0,992\%\end{matrix}\right.\)
c) \(V_{dd.A}=\dfrac{515}{1,25}=412\left(ml\right)=0,412\left(l\right)\)
\(\left\{{}\begin{matrix}C_{M\left(HCl.dư\right)}=\dfrac{1,54-1,4}{0,412}=0,34M\\C_{M\left(FeCl_2\right)}=\dfrac{0,1}{0,412}=0,243M\\C_{M\left(AlCl_3\right)}=\dfrac{0,4}{0,412}=0,971M\end{matrix}\right.\)