Đáp án đúng: D
0,09 mol hoặc 0,17 mol.
$\displaystyle \begin{array}{l}{{\text{n}}_{\text{A}{{\text{l}}^{\text{3+}}}}}\,\text{=}\,\text{0}\text{,1}\,\text{mol;}\,{{\text{n}}_{\text{Al(OH}{{\text{)}}_{\text{3}}}}}\,\text{=}\,\text{0}\text{,06}\,\text{mol}\\\text{TH1:}\,\,{{\text{n}}_{\text{O}{{\text{H}}^{\text{-}}}}}\,\text{=}\,\text{3}{{\text{n}}_{\text{O}{{\text{H}}^{\text{-}}}}}\,\text{=}\,\text{0}\text{,18}\,\text{mol}\,\Rightarrow \,\text{x=}\frac{{{\text{n}}_{\text{O}{{\text{H}}^{\text{-}}}}}}{\text{2}}\,\text{=}\,\text{0}\text{,09}\,\text{mol}\\\text{TH2:}\,\,{{\text{n}}_{\text{Al(OH)}_{\text{4}}^{\text{-}}}}\,\text{=}\,{{\text{n}}_{\text{A}{{\text{l}}^{\text{3+}}}}}\,\text{-}\,{{\text{n}}_{\text{Al(OH}{{\text{)}}_{\text{3}}}}}\,\text{=}\,\text{0}\text{,04}\\{{\text{n}}_{\text{O}{{\text{H}}^{\text{-}}}}}\,\text{=}\,\text{3}{{\text{n}}_{\text{Al(OH}{{\text{)}}_{\text{3}}}}}\,\text{+}\,\text{4}{{\text{n}}_{\text{Al(OH)}_{\text{4}}^{\text{-}}}}\,\text{=}\,\text{0}\text{,34}\,\Rightarrow \,\text{x=}\frac{{{\text{n}}_{\text{O}{{\text{H}}^{\text{-}}}}}}{\text{2}}\,\text{=}\,\text{0}\text{,17}\,\text{mol}\end{array}$
