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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