Em tham khảo nha :
\(\begin{array}{l}
6)\\
C\\
S{O_3} + {H_2}O \to {H_2}S{O_4}\\
7)\\
B\\
{n_{NaOH}} = \dfrac{{20}}{{40}} = 0,5mol\\
{C_{{M_{NaOH}}}} = \dfrac{{0,5}}{{0,2}} = 2,5M\\
8)\\
D\\
NaOH\,15\% \\
{m_{NaOH}} = \dfrac{{{m_{dd}} \times 15}}{{100\% }}\\
NaOH\,18\% \\
{m_{NaOH}} = \dfrac{{({m_{dd}} - 15) \times 18}}{{100}}\\
\Rightarrow \dfrac{{{m_{dd}} \times 15}}{{100\% }} = \dfrac{{({m_{dd}} - 15) \times 18}}{{100}}\\
\Rightarrow {m_{dd}} = 90g\\
9)\\
A\\
10)\\
A
\end{array}\)
