This addition reaction occurs in alkenes and alkynes. Hydrogen gas is added with the help of a catalyst. Nickel (Ni) or platinum (Pt) metal can be used.
We can also call this reaction reaction Sabatier-Senderens. It is well known in the food chemical industry, serving as the basis for the production of margarines from vegetable oils.
Vegetable oils have double bonds. The addition reaction, catalytic hydrogenation, transforms these oils (which are liquid) into fats (which are solid).
Oil + nH2 → fat
Catalytic hydrogenation in alkenes and alkynes:
Note that the product of this reaction is an alkane. So one of the alkane syntheses is catalytic hydrogenation.