a) Gọi số mol FeO, Al2O3 là a, b (mol)
=> 72a + 102b = 21 (1)
\(n_{HCl}=\dfrac{200.16,425\%}{36,5}=0,9\left(mol\right)\)
PTHH: FeO + 2HCl --> FeCl2 + H2O
a---->2a-------->a
Al2O3 + 6HCl --> 2AlCl3 + 3H2O
b------>6b------>2b
=> 2a + 6b = 0,9 (2)
(1)(2) => a = 0,15 (mol); b = 0,1 (mol)
\(\left\{{}\begin{matrix}\%m_{FeO}=\dfrac{0,15.72}{21}.100\%=51,43\%\\\%m_{Al_2O_3}=\dfrac{0,1.102}{21}.100\%=48,57\%\end{matrix}\right.\)
b) mdd sau pư = 21 + 200 = 221 (g)
mFeCl2 = 0,15.127 = 19,05 (g)
mAlCl3 = 0,2.133,5 = 26,7 (g)
\(\left\{{}\begin{matrix}C\%_{FeCl_2}=\dfrac{19,05}{221}.100\%=8,62\%\\C\%_{AlCl_3}=\dfrac{26,7}{221}.100\%=12,08\%\end{matrix}\right.\)
