Physical properties of matter: melting and boiling point

Question

a student measured the melting point range of an unknown solid to be 72.4 to 78.6 degrees Celsius.

1. is it the compound pure?
2. can you identify the compound?

Answer 1

This is a fairly large range. The transition between the solid and the liquid is so sharp for small samples of a pure substance that melting points can be measured to 0.1^oC. Therefore, not sure that it could be identified.