A continuous multi-stage distillation column processes a binary mixture. The mole fraction of the more volatile component in the distillate is 0.9. The reflux ratio is 2.9. At which vapour mole...

A continuous multi-stage distillation column processes a binary mixture. The mole fraction of the more volatile component in the distillate is 0.9. The reflux ratio is 2.9. At which vapour mole fraction, yy, does the rectification operating line cut the y-axis?