a, Bảo toàn e:
\(2n_{Zn}=2n_{H_2}\)
\(\Leftrightarrow n_{Zn}=n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow m_{Zn}=19,5\left(g\right)\)
PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
b, Bảo toàn nguyên tố H:
\(n_{HCl}=2n_{H_2}=0,6\left(mol\right)\)
\(\Rightarrow m_{HCl}=21,9\left(g\right)\)