Out-of-the-box Stoichiometry problem?

Note that Cu does not react with HCl.

(77.1 % of 35.0 g) / (26.98154 g Al/mol) = 1.0001 mol Al
(0.750 L) x (3.00 mol/L HCl) = 2.25 mol HCl

2.25 moles of HCl would react completely with 2.25 x (2/6) = 0.75 mole of Al, but there is more Al present than that, so Al is in excess and HCl is the limiting reactant.

(2.25 mol HCl) x (3 mol H2 / 6 mol HCl) x (2.015894 g H2/mol) = 2.27 g H2