Cho 400 ml dung dịch E gồm AlCl3 x mol/lít và Al2(SO4)3 y mol/lít tác dụng với 612

Đáp án D.

$$\begin{gathered} \left\{\begin{array}{l}AlC{l}_3:0,4x\\ A{l}_2{\left(S{O}_4\right)}_3:0,4y\end{array}\right.\stackrel{BaC{l}_2}{\to }BaS{O}_4:33,552 \\ \to n_{BaS{O}_4}=0,144\to n_{A{l}_2{\left(S{O}_4\right)}_3}=\frac{1}{3}{n}_{BaS{O}_4}=0,048\to y=0,12 \\ \left\{\begin{array}{l}AlC{l}_3:0,4x\\ A{l}_2{\left(S{O}_4\right)}_3:0,048\end{array}\right.\stackrel{NaOH:0,612}{\to }Al{\left(OH\right)}_3:8,424\to n_{Al{\left(OH\right)}_3}=0,108 \\ A{l}^{3+}+ 3O{H}^{-}\to Al{\left(OH\right)}_3 \end{gathered}$$

0,108         0,324  0,108

$A{l}^{+}+ 4O{H}^{-}\to Al{O}_2^{-}+2H_{2}O$

0,072 $(0,612-0,324)$

$$\begin{gathered} \to n_{A{l}^{3+}}=0,108+0,072=0,18\to 0,4x+0,048.2=0,45\to x=0,21 \\ \to x:y=7:4. \end{gathered}$$