\(\begin{array}{l}
a)\\
C{O_2} + 2NaOH \to N{a_2}C{O_3} + {H_2}O\\
nC{O_2} = \frac{{5,6}}{{22,4}} = 0,25mol\\
nNaOH = 2nC{O_2} = 0,5mol\\
nN{a_2}C{O_3} = nC{O_2} = 0,25mol\\
VNaOH = \frac{{0,5}}{{0,2}} = 2,5l\\
CMN{a_2}C{O_3} = \frac{{0,25}}{{2,5}} = 0,1\,mol\\
b)\\
NaOH + C{O_2} \to NaHC{O_3}\\
nNaHC{O_3} = nC{O_2} = nNaOH = 0,25mol\\
VNaOH = \frac{{0,25}}{{0,2}} = 1,25l\\
CMNaHC{O_3} = \frac{{0,25}}{{1,25}} = 0,2\\
c)\\
1 < \frac{{nNaOH}}{{0,25}} < 2\\
= > 0,25 < nNaOH < 0,5\\
= > 1,25 < VNaOH < 2,5
\end{array}\)