How many moles of hydrogen gas will be produced if 25g of Na reacts completely with excess HCl?

Answer 1

Balanced equation first.

2Na + 2HCl >> 2NaCl + H2

25 grams Na (1mol Na/22.99g )(1mol H2/2mol Na ) = 0.54 moles of H2 produced.

Answer 2

Using the equation 2Na + 2HCl -> 2NaCl + H2, we can see that 2 moles of Na react with 2 moles of HCl to produce 1 mole of H2. Calculate moles of Na: 25g Na * 1 mol Na / 23g Na = 1.09 mol Na. Since the reaction is with excess HCl, the number of moles of H2 produced will be half the number of moles of Na, so it will be 0.545 moles of H2.