Question

Why does sodium chloride dissolve in water? Is not the dissolution of salt in water endothermic?

Answer 1

........because God wanted it that way.......

Explanation:

The dissolution of sodium chloride in water is SLIGHTLY endothermic........i.e.

`NaCl(s) + Deltastackrel(H_2O)rarrNa^(+) + Cl^-`

But on the other hand, even tho' each ionic particle is solvated by several water molecules, the entropy of the reaction is positive.....in that the highly ordered crystalline `NaCl` lattice is broken up to give the solvated ions which have a greater statistical probability for disorder, a greater `"entropy"`....

Given that `DeltaG^@=DeltaH^@-TDeltaS^@`, and `DeltaG^@` is the single, unequivocal criterion for the spontaneity of chemical change..........

.....the increase in entropy can account for the `+DeltaH^@`, and the given reaction is spontaneous........i.e. `DeltaG^@<0`........