By the process of calcanation
thank you
its not calcination....calcination is a method used in extraction of metals
Vegetable oils are unsaturated compounds containing double bonds.They are liquid at room temperature.Due to the presence of double bonds, vegetable oils undergo addition reaction with hydrogen just like alkenes to form saturated compounds called vegetable ghee or vanaspati ghee which are solid or semi solid at room temperature.This process is called hydrogenation of oils.

are you answering from the book S . CHAND [PHYSICS]?
no....this is from my lecture serious
plus idk who is chand n all...i dont hav any such books
oḥ.ok i m sorry
no needsry nall