Quy hỗn hợp X về : \(\left\{{}\begin{matrix}Na:x\left(mol\right)\\Ba:y\left(mol\right)\\O:z\left(mol\right)\end{matrix}\right.\)
BTe ta được : \(x+2y=2z+0,05.2\left(1\right)\)
BTKL : \(23x+137y+16z=21,9\left(2\right)\)
\(y=\dfrac{20,52}{171}=0,12\left(mol\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=0,14\\z=0,14\end{matrix}\right.\)
\(n_{NaOH}=0,14\Leftrightarrow a=0,14.40=5.6\left(g\right)\)