Zn + H2SO4---->ZnSO4 + H2
1mol 1mol 1mol 1mol
md H2SO4=576,47*68/100=391,99= aprox. 392 g
392g H2SO4=4moli H2SO4
din ecuatie ==> n ZnSO4= 4 moli m ZnSO4= 4*161 g
n H2= 4 moli
nZn=4moli => m Zn= 4*65 g=260g
p(puritatea)= m pur*100/m impur
p=260*100/270=96,2 %