Calcium reacts with water to produce Calcium Hydroxide and Hydrogen gas;
Ca + 2 H₂O → Ca(OH)₂ + H₂
According to balance equation,
40 g (1 mole) Ca reacts to form = 22.4 L (1 mole) H₂
So,
20.1 g of Ca will produce = X L of H₂
Solving for X,,
X = (22.4 L × 20.1 g) ÷ 40 g
X = 11.25 L
Result:
Theoretical Yield of H₂ at STP = 11.25 Liter