Ta có:
\(\left\{{}\begin{matrix}n_{MnO2}=\frac{69,6}{87}=0,8\left(mol\right)\\n_{NaOH}=0,5.4=2\left(mol\right)\end{matrix}\right.\)
\(MnO_2+4HCl\rightarrow MnCl_2+Cl_2+2H_2O\)
0,8_________________________0,8____
\(Cl_2+2NaOH\rightarrow NaCl+NaClO+H_2O\)
0,8____1,6________0,8_______0,8______
\(V_{dd\left(pư\right)}=500\left(ml\right)=0,5\left(l\right)\)
\(\left\{{}\begin{matrix}CM_{NaCl}=CM_{NaClO}=\frac{0,8}{0,5}=1,6M\\CM_{NaOH\left(dư\right)}=\frac{0,4}{0,5}=0,8M\end{matrix}\right.\)