Final answer:
Salt does not melt when heated, but undergoes dissociation. The time it takes for salt to fully dissociate depends on the temperature and size of the salt crystals.
Step-by-step explanation:
When salt is heated, it does not melt like sugar does. Salt actually undergoes a process called dissociation, where the sodium and chloride ions separate from each other. This means that the salt crystals do not melt, but rather break apart to form a solution in the water.
The time it takes for salt to dissociate depends on the temperature and the size of the salt crystals. Generally, smaller salt crystals will dissociate faster than larger ones. To estimate the time it takes for salt to fully dissociate, you can observe when the salt crystals have completely disappeared in the water.