Đáp án:

 86,016l

Giải thích các bước giải:

\(\begin{array}{l}
V{C_2}{H_5}OH = \dfrac{{V{\rm{dd}} \times Dr}}{{100}} = \dfrac{{45 \times 200}}{{100}} = 90ml\\
V{H_2}O = 200 - 90 = 110ml\\
m{C_2}{H_5}OH = 90 \times 0,8 = 72g\\
m{H_2}O = 110 \times 1 = 110g\\
n{C_2}{H_5}OH = \dfrac{m}{M} = \dfrac{{72}}{{46}} = \dfrac{{36}}{{23}}\,mol\\
n{H_2}O = \dfrac{n}{M} = \dfrac{{110}}{{18}} = \dfrac{{55}}{9}\,mol\\
2{C_2}{H_5}OH + 2Na \to 2{C_2}{H_5}ONa + {H_2}\\
2{H_2}O + 2Na \to 2NaOH + {H_2}\\
n{H_2} = \dfrac{{36}}{{23}} \times \dfrac{1}{2} + \dfrac{{55}}{9} \times \dfrac{1}{2} = 3,84\,mol\\
V{H_2} = n \times 22,4 = 3,84 \times 22,4 = 86,016l
\end{array}\)