Em tham khảo nha :
\(\begin{array}{l}
2)\\
2Na + 2{H_2}O \to 2NaOH + {H_2}\\
{n_{{H_2}}} = \dfrac{{1,12}}{{22,4}} = 0,05mol\\
{n_{NaOH}} = 2{n_{{H_2}}} = 0,1mol\\
{C_{{M_{NaOH}}}} = \dfrac{{0,1}}{{0,2}} = 0,5M\\
7)\\
2Al + 6HCl \to 2AlC{l_3} + 3{H_2}\\
{n_{Al}} = \dfrac{{3,24}}{{27}} = 0,12mol\\
{n_{{H_2}}} = \dfrac{3}{2}{n_{Al}} = 0,18mol\\
{V_{{H_2}}} = 0,18 \times 22,4 = 4,032l\\
8)\\
Mg + {H_2}S{O_4} \to MgS{O_4} + {H_2}\\
{n_{{H_2}}} = \dfrac{{2,24}}{{22,4}} = 0,1mol\\
{n_{Mg}} = {n_{{H_2}}} = 0,1mol\\
{m_{Mg}} = 0,1 \times 24 = 2,4g
\end{array}\)