a,
\(MnO_2+4HCl\rightarrow MnCl_2+Cl_2+2H_2O\)
\(\Rightarrow n_{MnO2}=n_{Cl2}=0,4\left(mol\right)\)
\(\Rightarrow V_{Cl2}=0,4.22,4=8,96\left(l\right)\)
b,
\(n_{NaOH}=1\left(mol\right)\)
\(Cl_2+2NaOH\rightarrow NaCl+NaClO+H_2O\)
\(\Rightarrow n_{NaCl}=n_{NaClO}=0,4\left(mol\right)\)
Dư 0,2 mol NaOH
\(CM_{NaCl}=CM_{NaClO}=\frac{0,4}{0,5}=0,8M\)
\(CM_{NaOH}=\frac{0,2}{0,5}=0,4M\)