Suppose hydrogen Xg:
2h2o = 2h2 =+O2 = (electrolysis)
2× 18 2×2
1.8 x
36 : 1.8 = 4 : x
Solution: x = 0.2
Answer: 0.2g hydrogen is generated.
According to the molecular formula of water and the mass fraction of hydrogen in water:
1.8g×2/ 18× 100% = 0.2g
Answer: 0.2g hydrogen is generated.