2026 · Q109
Which one of the following processes is not used for the production of hydrogen gas?
general-sciencechemistry
- AElectrolytic process
- BWater gas-steam process
- CLiquefaction of coal gas
- DHydrolysis of calcium carbide
Explanation
Hydrogen is produced by electrolysis of water, by the steam reforming/water-gas process, and from coal gas; but the hydrolysis of calcium carbide yields acetylene (C₂H₂), not hydrogen. The reaction CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂ is the classic laboratory route to acetylene. Hence option D is the process not used for hydrogen production.