PART_25 WHAT IS HARDING OILS?Hardening of Vegetable OilHardening of oils or hydrogenation is the process also called the hydrogenation process, in which the vegetable oil is hardened by heating a mixture of vegetable oil and a catalyst in a nearly vacuum environment to extremely high temperatures and then adding hydrogen.What is it called when oil hardens?A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature.What is used to harden oil?HydrogenationHydrogenation is the process of adding hydrogen to a substance to solidify its unsaturated lipids or fatty acids.What is the hardening process?Hardening involves controlled heating to a critical temperature dictated by the type of steel (in the range 760-1300 C) followed by controlled cooling.Well! Thanks for all!