Chemical reactions... I don't think I have any more hair to pull out!?

Question

For the reaction 2Al + 6HCI3 -> 2AlCI3 + 3H2 how many moles of H2 are produced by the complete reaction of 4.90 moles of Al?

Answer 1

Try this:
2Al + 6HCl --> 2AlCl3 + 3H2
2 Al ~ 3H2
Mol H2 = 4.90 mol Al x 3H2/2Al = 4.90 x 1.5 =7.35 mol H2

Answer 2

You wouldn't have to pull out THAT much hair if you understood WHY you need these reactions. To answer your question, you only need to form a proportion:
4.9 moles Al/2 = x moles H2/3