Giải thích các bước giải:
\(\begin{array}{l}
N{a_2}O + 2HCl \to 2NaCl + {H_2}O\\
MgO + 2HCl \to MgC{l_2} + {H_2}O\\
NaOH + HCl \to NaCl + {H_2}O\\
{n_{N{a_2}O}} = 0,1mol\\
{n_{MgO}} = 0,1mol\\
{n_{NaOH}} = 0,01mol\\
a)\\
{n_{HCl}} = 2{n_{N{a_2}O}} + 2{n_{MgO}} + {n_{NaOH}} = 0,4mol\\
\to {m_{HCl}} = 0,4 \times 36,5 = 14,6g\\
\to {m_{{\rm{dd}}HCl}} = \dfrac{{14,6}}{{20\% }} \times 100\% = 73g\\
b)\\
{n_{NaCl}} = 2{n_{N{a_2}O}} = 0,2mol \to {m_{NaCl}} = 11,7g\\
{n_{MgC{l_2}}} = {n_{MgO}} = 0,1mol \to {m_{MgC{l_2}}} = 9,5g\\
\to {m_{{\rm{dd}}}} = {m_X} + {m_{{\rm{dd}}HCl}} = 6,2 + 4 + 73 = 83,2g\\
\to C{\% _{NaCl}} = \dfrac{{11,7}}{{83,2}} \times 100\% = 14,06\% \\
\to C{\% _{MgC{l_2}}} = \dfrac{{9,5}}{{83,2}} \times 100\% = 11,42\%
\end{array}\)