Đáp án đúng: A
84% và 16%.
$\displaystyle \begin{array}{l}\text{2NaHC}{{\text{O}}_{\text{3}}}\,\xrightarrow{{{\text{t}}^{\text{o}}}}\,\text{N}{{\text{a}}_{\text{2}}}\text{C}{{\text{O}}_{\text{3}}}\,\text{+}\,\text{C}{{\text{O}}_{\text{2}}}\,\text{+}\,{{\text{H}}_{\text{2}}}\text{O}\\{{\text{m}}_{\text{C}{{\text{O}}_{\text{2}}}}}\,\text{+}\,{{\text{m}}_{{{\text{H}}_{\text{2}}}\text{O}}}\,\text{=}\,\text{10}\,\text{-}\,\text{6,9}\,\text{=}\,\text{3,1}\,\text{gam}\\\Rightarrow {{\text{n}}_{\text{C}{{\text{O}}_{\text{2}}}}}\,\text{=}\,{{\text{n}}_{{{\text{H}}_{\text{2}}}\text{O}}}\,\text{=}\,0,05\,\text{mol}\Rightarrow {{\text{n}}_{\text{NaHC}{{\text{O}}_{\text{3}}}}}\,\text{=}\,\text{0,1}\,\text{mol}\\\Rightarrow {{\text{m}}_{\text{NaHC}{{\text{O}}_{\text{3}}}}}\,\text{=}\,8,4\,\text{gam}\,\Rightarrow \,{\scriptstyle{}^{\text{o}}\!\!\diagup\!\!{}_{\text{o}}\;}\text{NaHC}{{\text{O}}_{\text{3}}}\,\text{=}\,84{\scriptstyle{}^{\text{o}}\!\!\diagup\!\!{}_{\text{o}}\;}\end{array}$
