Đáp án đúng: D
300 hoặc 700.
TH1:
$\begin{array}{l}\text{HCl}\,\text{+}\,\text{NaOH}\,\xrightarrow{{}}\,\text{NaCl}\,\text{+}\,{{\text{H}}_{\text{2}}}\text{O}\\\,\,\text{0,2}\,\,\leftarrow \,\,\text{0,2}\\\text{HCl}\,\text{+}\,\text{NaAl}{{\text{O}}_{\text{2}}}\,\text{+}\,{{\text{H}}_{\text{2}}}\text{O}\,\xrightarrow{{}}\,\text{NaCl}\,\text{+}\,\text{Al(OH}{{\text{)}}_{\text{3}}}\\\,\,\text{0,1}\,\,\leftarrow \,\text{0,1}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\xleftarrow{{}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\text{0,1}\\\Rightarrow \,{{\text{n}}_{\text{HCl}}}\,\text{=}\,\text{0,3}\end{array}$
TH2:
$\begin{array}{l}\text{HCl}\,\text{+}\,\text{NaOH}\,\xrightarrow{{}}\,\text{NaCl}\,\text{+}\,{{\text{H}}_{\text{2}}}\text{O}\\\,\,\text{0,2}\,\,\leftarrow \,\,\text{0,2}\\\text{HCl}\,\text{+}\,\text{NaAl}{{\text{O}}_{\text{2}}}\,\text{+}\,{{\text{H}}_{\text{2}}}\text{O}\,\xrightarrow{{}}\,\text{NaCl}\,\text{+}\,\text{Al(OH}{{\text{)}}_{\text{3}}}\\\,\,\text{0,2}\,\,\leftarrow \,\text{0,2}\\\text{3HCl}\,\,\,\text{+}\,\,\text{Al(OH}{{\text{)}}_{3}}\,\xrightarrow{{}}\,AlC{{l}_{3}}\,+\,3{{H}_{2}}O\\\,0,3\,\,\leftarrow \text{(0,2-0,1)}\\\Rightarrow \,{{\text{n}}_{\text{HCl}}}\,\text{=}\,\text{0,7}\end{array}$
