Em tham khảo nha :
\(\begin{array}{l}
a)\\
N{a_2}O + 2HCl \to 2NaCl + {H_2}O\\
BaO + 2HCl \to BaC{l_2} + {H_2}O\\
b)\\
hh:N{a_2}O(a\,mol);BaO(b\,mol)\\
\left\{ \begin{array}{l}
62a + 153b = 40,1\\
117a + 208b = 67,6
\end{array} \right.\\
\Rightarrow a = 0,4;b = 0,1\\
{m_{N{a_2}O}} = 0,4 \times 62 = 24,8g\\
{m_{BaO}} = 0,1 \times 153 = 15,3g
\end{array}\)