\(n_{Na_2O}=\dfrac{6.2}{62}=0.1\left(mol\right)\)
\(Na_2O+H_2O\rightarrow2NaOH\)
\(0.1.......................0.2\)
\(C\%_{NaOH}=\dfrac{0.2\cdot40}{200}\cdot100\%=4\%\)
\(2NaOH+CO_2\rightarrow Na_2CO_3+H_2O\)
\(0.2..................0.1\)
\(V_{CO_2}=0.1\cdot22.4=2.24\left(l\right)\)