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

1 Answer
anor277
Jul 8, 2017

........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#........

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