Đáp án đúng: C 10,2. $\begin{array}{l}\text{2Al(OH}{{\text{)}}_{\text{3}}}\xrightarrow{{{\text{t}}^{\text{o}}}}\text{A}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\text{+3}{{\text{H}}_{\text{2}}}\text{O}\\\Rightarrow {{\text{n}}_{\text{A}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}}}\text{=0}\text{,1}\ \text{mol}\Rightarrow \text{m=10}\text{,2}\ \text{gam}\end{array}$