Mg+H2SO4⇒MgSO4+H2
MH2SO4=98
1mol Mg-------1mol acid
0,4moliMg-----X
X=0,4moliH2SO4×98=39,2gacid
C%=md/ms×100
ms=md×100/C
ms=80g solutie acid C%49
1mol Mg---------1molH2
0,4moli------------y
y=0,4moliH2×2=0,8gH2
22,4lH2-----------2gH2
V l----------------------0,8g
V=8,96lH2