(a) Both fog and cloud are the examples in which liquid (water) is the dispersed phase and gas (air) is the dispersion medium. The only difference between them is that clouds are formed in the upper atmosphere while fog gets formed in the region close to earth.
(b) A fractionating column obstructs the upwards movement of the vapours of the liquids. As a result, the energy (latent heat of condensation) which is released by the high boiling liquid is taken by the low boiling liquid. It remains in the vapour state. The high boiling liquid by releasing energy condenses and falls back in the distillation flask. Thus, fractionating column helps in the separation of the components from a liquid mixture. For example, a mixture of ethyl alcohol and water.
