$n_{Zn}=13/65=0,2mol$
$Zn+H_2SO_4\to ZnSO_4+H_2↑$
$\text{a/Theo pt :}$
$n_{H_2}=n_{Zn}=0,2mol$
$⇒V_{H_2}=0,2.22,4=4,48l$
$\text{b/Theo pt :}$
$n_{H_2SO_4}=n_{Zn}=0,2mol$
$⇒m_{H_2SO_4}=0,2.98=19,6g$
$⇒m_{ddH_2SO_4}=\dfrac{19,6}{24,5\%}=80g$
$\text{c/Theo pt :}$
$n_{H_2SO_4}=n_{Zn}=0,2mol$
$⇒C\%_{ZnSO_4}=\dfrac{0,2.161}{13+80-0,2.2}.100\%=34,77\%$