Em tham khảo nha:

\(\begin{array}{l}
2)\\
{C_M}MgC{l_2} = \dfrac{{0,5}}{{3,5}} = 0,14M\\
{n_{CuS{O_4}}} = \dfrac{{400}}{{160}} = 2,5\,mol\\
{C_M}CuS{O_4} = \dfrac{{2,5}}{5} = 0,5M\\
3)\\
a)\\
Fe + 2HCl \to FeC{l_2} + {H_2}\\
{n_{Fe}} = \dfrac{{11,2}}{{56}} = 0,2\,mol\\
{n_{{H_2}}} = {n_{Fe}} = 0,2\,mol\\
{V_{{H_2}}} = 0,2 \times 22,4 = 4,48l\\
b)\\
{n_{HCl}} = 2{n_{Fe}} = 0,4\,mol\\
{C_\% }HCl = \dfrac{{0,4 \times 36,5}}{{200}} \times 100\%  = 7,3\% \\
c)\\
{m_{{\rm{dd}}spu}} = 11,2 + 200 - 0,2 \times 2 = 210,8g\\
{n_{FeC{l_2}}} = {n_{Fe}} = 0,2\,mol\\
{C_\% }FeC{l_2} = \dfrac{{0,2 \times 127}}{{210,8}} \times 100\%  = 12,05\% 
\end{array}\)