Đáp án:
a) a=0,75
b) 21,7g
Giải thích các bước giải:
\(\begin{array}{l}
a)\\
S{O_2} + 2NaOH \to N{a_2}S{O_3} + {H_2}O\\
S{O_2} + NaOH \to NaHS{O_3}\\
hh:N{a_2}S{O_3}(a\,mol),NaHS{O_3}(b\,mol)\\
{n_{S{O_2}}} = \dfrac{{2,24}}{{22,4}} = 0,1\,mol\\
\left\{ \begin{array}{l}
a + b = 0,1\\
126a + 104b = 11,5
\end{array} \right.\\
\Rightarrow a = b = 0,05\,mol\\
{n_{NaOH}} = 0,05 \times 2 + 0,05 = 0,15\,mol\\
{C_M}NaOH = \dfrac{{0,15}}{{0,2}} = 0,75M \Rightarrow a = 0,75\\
b)\\
2NaHS{O_3} + Ba{(OH)_2} \to N{a_2}S{O_3} + BaS{O_3} + 2{H_2}O(1)\\
{n_{N{a_2}S{O_3}(1)}} = {n_{BaS{O_3}(1)}} = \dfrac{{0,05}}{2} = 0,025\,mol\\
{n_{N{a_2}S{O_3}}} = 0,05 + 0,025 = 0,075\,mol\\
N{a_2}S{O_3} + Ba{(OH)_2} \to 2NaOH + BaS{O_3}(2)\\
{n_{BaS{O_3}(2)}} = {n_{N{a_2}S{O_3}}} = 0,075\,mol\\
{m_{BaS{O_3}}} = (0,025 + 0,075) \times 217 = 21,7g
\end{array}\)
