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

Jul 8, 2017

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

#### Explanation:

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

$N a C l \left(s\right) + \Delta \stackrel{{H}_{2} O}{\rightarrow} N {a}^{+} + C {l}^{-}$

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 $N a C l$ lattice is broken up to give the solvated ions which have a greater statistical probability for disorder, a greater $\text{entropy}$....

Given that $\Delta {G}^{\circ} = \Delta {H}^{\circ} - T \Delta {S}^{\circ}$, and $\Delta {G}^{\circ}$ is the single, unequivocal criterion for the spontaneity of chemical change..........

.....the increase in entropy can account for the $+ \Delta {H}^{\circ}$, and the given reaction is spontaneous........i.e. $\Delta {G}^{\circ} < 0$........