a)\(16HCl+2KMnO4-->5Cl2+8H2O+2KCl+2MnCl2\)
\(n_{KMnO4}=\frac{15,8}{158}=0,1\left(mol\right)\)
\(n_{Cl2}=\frac{5}{2}n_{KMnO4}=0,25\left(mol\right)\)
\(V_{Cl2}=0,25,22,5=5,6\left(l\right)\)
b)\(n_{HCl}=8n_{KMnO4}=0,8\left(mol\right)\)
\(V_{HCl}=\frac{0,8}{8}=0,1\left(l\right)\)