Cho dung dịch X gồm \(0,08~\text{mol}\,\,\,\text{A}{{\text{l}}_{2}}{{\left( \text{S}{{\text{O}}_{4}} \right)}_{3}}\) và \(0,12~\,\text{mol}\,\,\,{{\text{H}}_{2}}\text{S}{{\text{O}}...

* Hướng dẫn giải

Đáp án B.

\(X\left\{ \begin{array}{*{35}{l}} \text{A}{{\text{l}}_{2}}{{\left( \text{S}{{\text{O}}_{4}} \right)}_{3}}:0,08 \\ {{\text{H}}_{2}}\text{S}{{\text{O}}_{4}}:0,12 \\ \end{array}\to \right.\left\{ \begin{array}{*{35}{l}} \begin{align} & \text{BaS}{{\text{O}}_{4}} \\ & \text{Al}{{(\text{OH})}_{3}} \\ \end{align} \\ \end{array}\to \left\{ \begin{array}{*{35}{l}} \text{A}{{\text{l}}_{2}}{{\text{O}}_{3}} \\ \text{BaS}{{\text{O}}_{4}} \\ \end{array} \right. \right.\)

\(\begin{align} & {{\text{H}}^{+}}+\text{O}{{\text{H}}^{-}}\to {{\text{H}}_{2}}\text{O} \\ & 0,24\,\,\,0,8 \\ \end{align}\)

\(\mathrm{Al}^{3+}+3 \mathrm{OH}^{-} \rightarrow \mathrm{Al}(\mathrm{OH})_{3}\)

\(0,16\quad 0,48\quad \,\,\,\,\,0,16\)

\(\mathrm{Al}(\mathrm{OH})_{3}+\mathrm{OH}^{-} \rightarrow \mathrm{AlO}_{2}^{-}+2 \mathrm{H}_{2} \mathrm{O}\)

    \(0,08 \leftarrow(0,8-0,24-0,48)\)

\({{n}_{\text{Al}{{(\text{OH})}_{3}}}}=0,16-0,08=0,08\)

\(\rightarrow n_{\mathrm{Al}_{2} \mathrm{O}_{3}}=0,04\)

\(\mathrm{Ba}^{2+}+\mathrm{SO}_{4}^{2-} \rightarrow \mathrm{BaSO}_{4}\)

\(0,4(0,24+0,12) \rightarrow 0,36\)

\(m={{m}_{\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}}}+{{m}_{\text{BaS}{{\text{O}}_{4}}}}=0,04.102+0,36.233=87,96\,(~\text{g})\)