What is a hydrogenation reaction? How is this reaction used in the ghee and oil industry?

Part 1:

1. An unsaturated hydrocarbon is the one in which there is the presence of double or triple bond between two adjacent Carbon atoms.
2. The addition of Hydrogen molecules to an unsaturated hydrocarbon is called Hydrogenation reaction. For example,

$$\begin{gathered} {\mathrm{C}}_2{\mathrm{H}}_4\left(\mathrm{g}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)\underset{}{\overset{\mathrm{Ni}/\mathrm{Pt},{250}^{\mathrm{o}}\mathrm{C}}{\to }}{\mathrm{C}}_2{\mathrm{H}}_6\left(\mathrm{g}\right) \\ \mathrm{Ethene}\mathrm{Hydrogen}\mathrm{Ethane} \end{gathered}$$

Part 2:

1. The hydrogenation process is used to prepare vegetable ghee from vegetable oil.
2. Vegetable oils like Cottonseed oil, groundnut oil, etc. have double or triple bonds in their molecule.
3. They are converted to ghee by Hydrogenation in the presence of Nickel.
4. This process of conversion of vegetable oil to a solid fat is called Hydrogenation of oils.

$\mathrm{Vegetable}\mathrm{oil}+{\mathrm{H}}_2\left(\mathrm{g}\right)\underset{}{\overset{\mathrm{Ni}/\mathrm{Pt}}{\to }}\mathrm{Vegetable}\mathrm{ghee}$