What is the process called that adds hydrogen to coal under high temperatures and pressures in the presence of a catalyst to create synthetic fuels?

• A. Hydrogenolysis
• B. Gasification
• C. Pyrolysis
• D. Hydrogenation

Answer: (D)

Hydrogenation is the process of adding hydrogen to unsaturated chemical structures to saturate them, typically using a metal catalyst under elevated temperature and pressure. In direct coal liquefaction, hydrogen is introduced to the coal under heat and pressure with a catalyst, breaking down the heavy material into lighter liquid hydrocarbons that become synthetic fuels. This differs from hydrogenolysis, which mainly involves breaking bonds with hydrogen; gasification, which turns coal into synthesis gas (CO and H2) for further synthesis; and pyrolysis, which thermally decomposes coal without oxygen to produce char, tar, and gas. So the scenario described fits hydrogenation.