\(n_{CO_2}=\dfrac{1,344}{22,4}=0,06\left(mol\right)\)
\(n_{Na_2CO_3}=\dfrac{3,18}{106}=0,03\left(mol\right)\)
Bảo toàn C: nC = 0,09 (mol)
Bảo toàn Na: nNa = 0,06 (mol)
\(n_{O_2}=\dfrac{6,72.20\%}{22,4}=0,06\left(mol\right)\)
Theo ĐLBTKL: mX + mO2 = mCO2 + mH2O + mNa2CO3
=> mH2O = 0,54 (g)
=> \(n_{H_2O}=\dfrac{0,54}{18}=0,03\left(mol\right)\)
Bảo toàn H: nH = 0,06 (mol)
=> \(\left\{{}\begin{matrix}\%C=\dfrac{12.0,09}{4,44}.100\%=24,33\%\\\%H=\dfrac{1.0,06}{4,44}.100\%=1,35\%\\\%Na=\dfrac{0,06.23}{4,44}.100\%=31,08\%\\\%O=100\%-24,33\%-1,35\%-31,08\%=43,24\%\end{matrix}\right.\)
=> B