An aluminum of mass 3.14gramm reacted with excess hydrochloride acid at stp according to the the following equation calculate the mass of hydrogen and the volume at stp
how many moles of Al do you have?
2Al + 6HCl = 2AlCl3 + 3H2
So, you get 3 moles of H2 for every 2 moles of Al
Now use the fact that 1 mole of a gas occupies 22.4L at STP.