MMg=24g/mol
MHCl=AH+ACl=1+35,5=36,5g/mol
n=m/M=2,4/24=0,1 moli Mg
n=m/M=14,6/36,5=0,4 moli HCl
a) Acid in exces -> 0,4-0,1=0,3 moli HCl (exces)
b) Mg + 2HCl -> MgCl2 + H2
1 mol Mg..........................1 mol H2
0,1 moli Mg.....................x=0,1 moli H2