Hydrogenation of vegetable oils using nickel catalyst is an example of

Step-by-step solution

Hydrogenation of oils in presence of palladium or nickel catalyst to form fat is an addition reaction. During hydrogenation, vegetable oils are reacted with hydrogen gas at about 60^ C . A nickel catalyst is used to speed up the reaction. The double bonds are converted to single bonds in the reaction. In this way unsaturated fats can be made into saturated fats - they are hardened.