Đáp án:

\(\begin{array}{l}
1.C{\% _{HCl}} = 4,56\% \\
2.C{\% _{HCl}} = 10,95\% 
\end{array}\)

Giải thích các bước giải:

1.

\(\begin{array}{l}
Fe + 2HCl \to FeC{l_2} + {H_2}\\
CuO + 2HCl \to CuC{l_2} + {H_2}O\\
{n_{{H_2}}} = 0,2mol\\
 \to {n_{Fe}} = 0,2mol\\
 \to {m_{Fe}} = 11,2g\\
 \to {m_{CuO}} = 24g \to {n_{CuO}} = 0,3mol\\
 \to {n_{HCl}} = 2{n_{Fe}} + 2{n_{CuO}} = 1mol\\
 \to {m_{HCl}} = 36,5g\\
 \to C{\% _{HCl}} = \dfrac{{36,5}}{{800}} \times 100\%  = 4,56\% 
\end{array}\)

2.

\(\begin{array}{l}
Mg + 2HCl \to MgC{l_2} + {H_2}\\
ZnO + 2HCl \to ZnC{l_2} + {H_2}O\\
{n_{{H_2}}} = 0,2mol\\
 \to {n_{Mg}} = 0,2mol\\
 \to {m_{Mg}} = 4,8g\\
 \to {m_{ZnO}} = 8,1g \to {n_{ZnO}} = 0,1mol\\
 \to {n_{HCl}} = 2{n_{Mg}} + 2{n_{ZnO}} = 0,6mol\\
 \to {m_{HCl}} = 21,9g\\
 \to C{\% _{HCl}} = \dfrac{{21,9}}{{200}} \times 100\%  = 10,95\% 
\end{array}\)