Final answer:
The melting point is used for identification, purity assessment, and determining the phase state of a substance.
Step-by-step explanation:
The melting point is used for several qualitative purposes:
- Identification: The melting point can be used to identify substances. Each substance has a unique melting point, so comparing the melting point of an unknown substance to known values can help determine its identity.
- Purity: The melting point can indicate the purity of a substance. Pure substances have a sharp melting point, while impurities can lower and broaden the melting range.
- Phase State: The melting point can indicate whether a substance is in a solid, liquid, or gas state at a given temperature. Below the melting point, the substance is solid, at the melting point it transitions to a liquid, and above the melting point it is a liquid.