Giải thích các bước giải:
\(\begin{array}{l}
CuC{l_2} + 2NaOH \to 2NaCl + Cu{(OH)_2}\\
Cu{(OH)_2} \to CuO + {H_2}O\\
a)\\
{n_{CuC{l_2}}} = 0,1mol\\
\to {n_{NaOH}} = 2{n_{CuC{l_2}}} = 0,2mol \to {m_{NaOH}} = 8g\\
\to C{\% _{NaOH}} = \dfrac{8}{{200}} \times 100\% = 4\% \\
{n_{Cu{{(OH)}_2}}} = {n_{CuC{l_2}}} = 0,1mol\\
\to {n_{CuO}} = {n_{Cu{{(OH)}_2}}} = 0,1mol\\
\to {m_{CuO}} = 8g\\
b)\\
{n_{NaCl}} = 2{n_{CuC{l_2}}} = 0,2mol \to {m_{NaCl}} = 5,85g\\
\to {m_{{\rm{dd}}X}} = {m_{CuC{l_2}}} + {m_{{\rm{dd}}NaOH}} - {m_{Cu{{(OH)}_2}}} = 203,7g\\
\to C{\% _{NaCl}} = \dfrac{{5,85}}{{203,7}} \times 100\% = 2,87\%
\end{array}\)