\(2Na+2H_2O\rightarrow2NaOH+H_2\)
\(\dfrac{a}{23}\) \(\dfrac{a}{23}\) \(\dfrac{a}{46}\) ( mol )
\(\Rightarrow C\%_{NaOH}=\dfrac{\dfrac{a}{23}.40}{a+45,6-\dfrac{a}{46}.2}.100=16\)
\(\Leftrightarrow a=4,6\left(g\right)\)
\(V=\left(\dfrac{4,6}{46}\right).22,4=2,24\left(l\right)\)
\(2Na+2H_2O\rightarrow2NaOH+H_2\\ n_{NaOH}=n_{Na}=\dfrac{a}{23}\left(mol\right)\\ m_{NaOH}=\dfrac{40a}{23}\left(g\right)\\ n_{H_2}=\dfrac{a}{46}\left(mol\right)\Rightarrow m_{H_2}=\dfrac{a}{23}\left(g\right)\\ C\%_{ddNaOH}=16\%\\ \Leftrightarrow\dfrac{\dfrac{40a}{23}}{a+45,6-\dfrac{a}{23}}.100\%=16\%\\ \Leftrightarrow a=m_{Na}=4,6\left(g\right)\\ n_{Na}=\dfrac{4,6}{23}=0,2\left(mol\right)\\ \Rightarrow n_{H_2}=\dfrac{0,2}{2}=0,1\left(mol\right)\\ \Rightarrow V=V_{H_2\left(đktc\right)}=0,1.22,4=2,24\left(l\right)\)
