Question

What difference in the properties of common salt and sand would enable you to separate a mixture of these two substances ?

Answer 1

The differences in the properties of common salt and sand that enable us to separate a mixture of these two substances are:
(a) Difference in the solubility of sand and salt. Salt is soluble in water, whereas sand is not. Therefore, we can separate sand from salt by taking water as solvent in the process of filtration.
(b) Salt is a solid that cannot vaporise. Thus, it can be obtained by the process of evaporation. In this process, all the water will evaporate leaving behind common salt.