The clear liquid was allowed to evaporate and after 3
days, only solids are left. Therefore this means that for the 3 days it was
exposed to air, some liquid or water perhaps was leaving out of the solution. Therefore
this means that the liquid was a mixture. It was a initially a mixture of the
solid residue plus the evaporated liquid.
It cannot be an element or a compound since both uniformly evaporates.
Answer:
Mixture
