Question

How many moles of H2 can be generated from .57 mol Al and .37 mol NaOH in excess water?.

Answer 1

For answering your questions you need to considerthe next equation:

2Al + 2NaOH + 6H₂O = 2Na[Al(OH)₄] + 3H₂

Al is in excess, so only 0.37 mol of it will react.

And about H₂. Amount if it is 0.37 * 3/2 = 0.555 moles