If an unknown has a melting point range of 104-107°C, what melting point range can you eliminate for purity?

When determining the purity of a substance, the melting point range serves as an important criterion. A pure substance typically exhibits a narrow melting point range, while impurities tend to broaden this range.

In this case, the given melting point range for the unknown compound is 104-107°C. To evaluate purity, if we consider values below the lower limit of this range (104°C), we can eliminate that range for the following reasons:

• Any substance melting below 104°C would not match the melting behavior of the unknown compound. Instead, such a lower melting point would suggest the presence of impurities or that the material is a different compound altogether. Hence, materials with melting points under 104°C can be confidently ruled out when assessing purity because a true melting point for the unknown must be at least 104°C.

Thus, the melting point range that can be eliminated for purity concerns is anything below 104°C.