# Why if the dissolution of sodium chloride in water is endothermic, is the reaction spontaneous?

Apr 13, 2017

The dissolution of sodium chloride in water is SLIGHTLY endothermic.

#### Explanation:

But the fundamental driving for the spontaneity of chemical change is not $\Delta H$, $\text{enthalpy change}$, but $\Delta S$, $\text{entropy change.}$ Certainly, when $\text{sodium chloride}$ reacts with water to form the aquated $\text{sodium}$ and $\text{chloride ions}$, the entropy INCREASES.........

$N a C l \left(s\right) + \text{excess } {H}_{2} O r i g h t \le f t h a r p \infty n s N {a}^{+} + C {l}^{-}$

${\Delta}_{\text{rxn}}$ is positive............and thus the reaction is spontaneous.