c,
$Zn+H_2SO_4\to ZnSO_4+H_2$
$Fe_2O_3+3H_2\buildrel{{t^o}}\over\to 2Fe+3H_2O$
d,
$n_{Zn}=\dfrac{19,5}{65}=0,3 mol$
$\Rightarrow n_{H_2SO_4}= n_{H_2}=0,3 mol$
$C\%_{H_2SO_4}=\dfrac{0,3.98.100}{150}=19,6\%$
e,
$n_{Fe}=\dfrac{2}{3}n_{H_2}=0,2 mol$
$\Rightarrow m=m_{Fe}=0,2.56=11,2g$