Organic Chemistry Question: Melting point and Eutectic Mixture?

Question

It is fairly common to find that at some definite composition, two substances form an eutectic mixture. For example, 1-naphthol melts at 95.5 Celcius and naphthalene melts at 80.5 Celcius. When mixtures of varying composition of these two substances are prepared it is found that the lowest melting point is obtained with a mixture consisting of 60.5 mol % naphthalene and 39.5 mol % of 1-naphthol. Such a mixture melts sharply at 61.0 Celcius. As this eutectic mixture melts, the composition of the melted mixture and the composition of the solid mixture remain unchanged, and as a consequence the melting temperature is constant. In terms of its melting point, such a mixture behaves like a pure substance. Given a sample of this eutectic mixture, how could you prove that it is not a pure substance? What would you do and what would you observe?

Answer 1

I would take the mixture, allegedly eutectic, and mix some of it with beaucoup naphthalene. The other part of the supposed euctectic mixture I would blend with beaucoup 1-naphthol. I would take the melting point of both preparations. If the melting points of each are above 61C (and safely below 95.5C and 80.5C (LOL), I should conclude that the original was not a pure substance, but a eutectic mixture.

Answer 2

boil it. If the two have seperate boiling points, you will be able to seperate them.