Hướng dẫn

Gọi ${{n}_{N{{a}_{2}}C{{O}_{3}}}}=x$, ${{n}_{{{K}_{2}}C{{O}_{3}}}}=y$

$N{{a}_{2}}C{{O}_{3}}+2HCl\to 2NaCl+C{{O}_{2}}+{{H}_{2}}O$          (1)

            x             $\to $                         x                      mol

${{K}_{2}}C{{O}_{3}}+2HCl\to 2KCl+C{{O}_{2}}+{{H}_{2}}O$ (2)

            y              $\to $                        y                      mol  

Theo bài ra ta có:
 $\begin{align}

  & {{m}_{N{{a}_{2}}C{{O}_{3}}}}+{{m}_{{{K}_{2}}C{{O}_{3}}}}=106x+138y=2,44\left( g \right) \\

 & {{n}_{C{{O}_{2}}}}=x+y=\frac{0,448}{22,4}=0,02\left( mol \right) \\

\end{align}$    

\[\Rightarrow \]  x=0,01   ;  y=0,01

$\Rightarrow {{n}_{N{{a}_{2}}C{{O}_{3}}}}={{n}_{{{K}_{2}}C{{O}_{3}}}}=0,01\left( mol \right)$ 

$%{{m}_{N{{a}_{2}}C{{O}_{3}}}}=\frac{0,01.106}{2,44}.100%=43,44%$ 

$\Rightarrow $ Chọn đáp án A