$n_{Zn}=6,5/65=0,1mol$
$a.Zn+2HCl\to ZnCl_2+H_2↑$
$\text{b.Theo pt :}$
$n_{H_2}=n_{Zn}=0,1mol$
$⇒V_{H_2}=0,1.22,4=2,24l$
$\text{c.Khi thu khí H2 phải đặt úp bình vì H2 nhẹ hơn kk}$
$d.2H_2+O_2\overset{t^o}\to 2H_2O$
$\text{Theo pt :}$
$n_{H_2O}=n_{H_2}=0,1mol$
$⇒m_{H_2O}=0,1.18=1,8g$