Giải thích các bước giải:

c,

\(\begin{array}{l}
{m_{HCl}} = \dfrac{{{m_{{\rm{dd}}}} \times 7,3\% }}{{100\% }} = \dfrac{{200 \times 7,3\% }}{{100\% }} = 14,6g\\
{n_{HCl}} = \dfrac{{14,6}}{{36,5}} = 0,4mol
\end{array}\)

d,

\(\begin{array}{l}
{m_{dd}} = {m_{ddnuoc}} + {m_{chat\tan }} = 100 + 36 = 136g\\
C\% NaCl = \frac{{{m_{chat\tan }}}}{{{m_{dd}}}} \times 100\%  = \frac{{36}}{{136}} \times 100\%  = 26,47\% 
\end{array}\)

e,

\(\begin{array}{l}
{m_{ddBaC{l_2}}} = \dfrac{{{m_{chat\tan }} \times 100\% }}{{20\% }} = \dfrac{{12 \times 100\% }}{{20\% }} = 60g\\
D = \dfrac{m}{V} \to V = \dfrac{m}{D} = \dfrac{{60}}{{1,2}} = 50ml
\end{array}\)