Problem with fractional distillation of a 60% isopropanol-40% distilled water mixture?

Question

the plateus that I got in this experiment are at 76 and 77 degrees celcius, are these results incorrect or what?

Answer 1

If your only plateau is at 76C then I would wonder if you actually have isopropanol (which has a boiling point of 82C).  Ethanol boils at 78C.  Ethanol seems like a more likely candidate.  And we will assume that you got another plateau at about 100C.

When you say you got plateaus at 76 and 77, are you suggesting two plateaus?  I would suggest that there is only one plateau.