# Can the experimental mole fraction equal one?

I recently did an experiment on the temperature dependence of phase equilibrium acetone $\ce{C3H6O_{(l)}} \to \ce{C3H6O_{(g)}}$ I'm at the stage where I need to find the experimental mole fraction $\chi_e$ which I did by plotting a graph (see below)

From this graph I can simply find $\chi_e$ by finding the slope. I took two points $(56,50)$ and $(66,60)$ and found $$\chi_e = 1$$

This doesn't look right to me, so I'm just asking if someone can let me know if what I've calculated is correct or way off the mark

EDIT: I just calculated the theoretical mole fraction there and got $$\chi_T = 0.94$$

The moles of the non-volatile solute and pure acetone were known.

• Hmmm... neither of the two points used in your calculation are on the line you've shown. – MaxW Oct 25 '17 at 20:38
• $(66,60)$ looks like it is, no? I've changed my other point and I'm getting $\chi_e > 1$ which is defintely bad. – Patrick Moloney Oct 25 '17 at 20:50