Question

Why is it important to maintain a uniform temperature gradient in a fractionating column?

Answer 1

Fractionating column works on the principle of partitioning between liquid and gaseous phase of a component. When heated the component of a mixture boils and goes in vapor state. At each fractionating column in the distillation unit, some of vapor gets recondensed into liquid phase and the vapor rises. This vaporisation and recondensation ensured absolute purity of the material distilled. Temperature during boiling of one component is maintained constant. If a large amount of heat is supplied instead, all of the liquid mixture would boil togther and no partition of liquid and vapor phase at any stage would occur. This would result in an inefficient distillation process with almost no separation of components of liquid mixture being distilled.