Question

Consider the reaction.

mc028-1.jpg

Which statement is true at STP? (The atomic mass of Zn is 65.39 u.)
2 mol of HCl produce 1 L of H2 gas.
1 L of Zn produces 1L of H2 gas.
65.39 g of Zn produce 22.4 L of H2 gas.
1 L of HCl produces 1 mol of H2 gas.

Answer 1

Reaction: Zn + 2 HCl → ZnCl2 + H2

1 mol Zn gives 1 mol H2. At STP 1 mol gas = 22.4 L. Since Zn atomic mass = 65.39 g/mol, 65.39 g Zn produces 1 mol H2 = 22.4 L.

So the true statement is: "65.39 g of Zn produce 22.4 L of H2 gas."