please help with this 5. List any problems with the following set up. oint Water
ID: 591272 • Letter: P
Question
please help with this
5. List any problems with the following set up. oint Water Joint adapter Clamp loint clip Heating The temperature at the head of a fractional distillation column was measured at selected times during the distillation of a mixture of toluene (bp. l 1° C) and hexane (bp. = 69° C). Initially, the temperature is 25°C. After a while, the temperature rises to-69° C, where it holds for several minutes. Then, the temperature drops briefly to- 40°C before rising again to 111° C, where it remains steady. Describe what is happening and what is causing each of these temperature changes. 6.Explanation / Answer
During fractional distillation ,of a mixture of two liquids toluene and hexane,the low boiling liquid(hexane b.pt 69 deg C) reaches its boiling point first as the temperature rises slowly in the fractionating column.At 69 deg C hexane boils and the temperature remains constant as the heat is getting used up in phase transition of hexane from liquid to vapours (latent heat of vaporisation).As all the vapours of hexane is condensed (condensed by cool water jet running in the cooling chamber or part of the long fractionating column) and separated from the column, the temperature of the column air cools down briefly (as detected by the detector at the head) .Again heating continued raises the temperature which rises gradually untill the high boiling liquid,toluene, starts boiling at 111 deg C.Again ,the heat is used up in phase transition of toluene so it remains steady untill all the toluene vapours condenses and gets separated by the cool condensing factors .
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