Describe how and explain why vegetable oils are hardened for use in foods. [5 marks]

Hydrogenation is used to add hydrogens to the vegetable oil molecules. This process gets rid of the double bonds in the molecular structure, making the molecules saturated, which lowers the melting point of the oil so that it is in a solid state at room teperature (margarine). This process occurs at 60 degrees Celcius, in the presence of a nickel catalyst.