The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n- octane into pure compounds each at 1 atm is
A. -2 RT ln 0.5
B. -RT ln 0.5
C. 0.5 RT
D. 2 RT
Answer: Option B
Solution (By Examveda Team)
Entropy of mixing is$$\eqalign{ & = - R\sum {{X_i}\ln {x_i}} \cr & = - R\left[ {0.5\,\ln \,0.5 + 0.5\,\ln \,0.5} \right] \cr} $$
Since, work $$ = T\Delta S = - RT\,\ln \,0.5.$$
This Question Belongs to Chemical Engineering >> Chemical Engineering Thermodynamics
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