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VAPOUR LIQUID

 EQUILIBRIUM

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 (a) a solution that shows positive deviation from

 Raoult's law

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(b) a solution that shows negative deviation from

 Raoult's law.

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Composition of liquid phase :

x1= p1/ p10

  =  partial pressure of component /vapour pressure of pure component

Composition in gaseous phase :y 1= p1/ P

  =  partial pressure of component /total pressureRaoult’s law becomes

yiP=xiPisat  i=1!"!#$%%n&

'here:

yi = (apor)phase mole fraction%xi = *i+ui,)phase mole fraction%

Pi = (apor pressure of pure species i at the - of the system%

yi P = Partial pressure of species i%

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VLE ! Modified Raoult"s La#

yi P = xi .i Pisat i= 1!"!$%%!&

'here

.i = ctivity coefficient%

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$%&%! dia'(am)oilin' point dia'(am

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A*ti+it! *oeffi*ient equations

  'ohl’s three suffix e+uation

  argules e+uation

  (an laar e+uation

  'ilson e+uation

   on ran,om two li+ui, R-*&e+uation

  2niversal +uasi 3chemical 2452C&e+uation

  2niversal functional activity coefficient 246C&metho,

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Consisten*! test fo( VLE data

  2sing slope of ln. curves

  2sing ,ata at mi, point

  Re,lich 37ister metho,

  2sing the coexistence e+uation

  2sing partial pressure ,ata

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Thank You