Name the reaction which is commonly used in the conversion of vegetable oils to fats. Explain the reaction involved in detail.

(N/A) The reaction used for the conversion of vegetable oils to fats is known as $Hydrogenation$.
$Hydrogenation$ is a chemical reaction in which hydrogen gas is added to unsaturated hydrocarbons (like vegetable oils containing double bonds) in the presence of a catalyst,such as $Nickel$ $(Ni)$,$Palladium$ $(Pd)$,or $Platinum$ $(Pt)$,to form saturated hydrocarbons (fats).
General reaction:
$R_2C=CR_2 + H_2 \xrightarrow{Ni \text{ catalyst}} R_2CH-CHR_2$
In this process,the $C=C$ double bond in the unsaturated oil molecule breaks,and two hydrogen atoms are added across the carbons,converting the liquid oil into a solid or semi-solid fat.