a)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
\(n_{Zn}=\frac{19,5}{65}=0,3\left(mol\right)\)
\(\Rightarrow n_{H2}=0,3\left(mol\right)\)
\(V_{H2}=0,3.22,4=6,72\left(l\right)\)
b)
\(n_{HCl}=0,6\left(mol\right)\)
\(\Rightarrow V_{HCl}=\frac{0,6}{1}=0,6\left(l\right)\)