How many moles of hydrogen gas will form if 0.35 moles of Na reacts with an excess of water?

Answer:
Write the balanced reaction equation. From this, note the mole ratio of Na to H₂; this enables you to know the number of moles of H₂ produced.
This technique is in your lecture notes and/or your chemistry textbook, so you should not have to ask Quorans to do your homework. (Take the hint.)
Explanation: