Em tham khảo nha :
\(\begin{array}{l}
a)\\
Mg + 2HCl \to MgC{l_2} + {H_2}\\
CuO + 2HCl \to CuC{l_2} + {H_2}O\\
{n_{{H_2}}} = \dfrac{{2,24}}{{22,4}} = 0,1mol\\
{n_{Mg}} = {n_{{H_2}}} = 0,1mol\\
{m_{Mg}} = 0,1 \times 24 = 2,4g\\
{m_{CuO}} = 4,4 - 2,4 = 2g\\
{n_{CuO}} = \dfrac{2}{{80}} = 0,025mol\\
{n_{MgC{l_2}}} = {n_{Mg}} = 0,1mol\\
{C_{{M_{MgC{l_2}}}}} = \dfrac{{0,1}}{{0,2}} = 0,5M\\
{n_{CuC{l_2}}} = {n_{CuO}} = 0,025mol\\
{C_{{M_{CuC{l_2}}}}} = \dfrac{{0,025}}{{0,2}} = 0,125M\\
b)\\
{n_{HCl}} = 2{n_{Mg}} + 2{n_{CuO}} = 0,25mol\\
{V_{HCl}} = \dfrac{{0,25}}{2} = 0,125l = 125ml
\end{array}\)