Answer:
12g
Step-by-step explanation:
The following equation is given in this question:
2H2 + O2 → 2H2O
According to this balanced chemical equation, 2 moles of hydrogen gas is used to produce 2 moles of water molecule.
Hence, if 12 grams of hydrogen is used, 12 × 2/2 = 24/2
= 12 grams of H2O will be produced.