The hydrocarbon feed to a distillation column is a bubble-point liquid at 300 psia with mole fractions: C₂ = 0.08, C₃ = 0.15, nC₄ = 0.20, nC₅ = 0.27, nC₆ = 0.20, and nC₇ = 0.10. Determine:

(a) Column pressure and type of condenser, if condenser outlet temperature is 120°F, for a sharp separation between nC₄ and nC₅; 

(b) At total reflux, the separation for eight theoretical stages overall, for 0.01 mole fraction nC₄ in the bottoms product; 

(c) Rmin for the separation in part (b); and 

(d) The number of theoretical stages, at R/R_min = 1.5, using the Gilliland correlation.