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

1 Answer
anor277
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 DeltaH, "enthalpy change", but DeltaS, "entropy change." Certainly, when "sodium chloride" reacts with water to form the aquated "sodium" and "chloride ions", the entropy INCREASES.........

NaCl(s) + "excess " H_2O rightleftharpoons Na^+ + Cl^(-)

Delta_"rxn" is positive............and thus the reaction is spontaneous.

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