The reaction between sodium chloride and water is slightly endothermic. Why does the reaction occur?

Answer 1

Because the process is #"entropy driven"#. What do I mean by this?

Chemical change is driven by #"(i) enthalpy, the latent heat of reaction"#, and #"(ii) entropy, the statistical probability of disorder"#.
The entropy change, #DeltaS^@#, is the more significant criterion.
When we write the #"Gibb's free energy"# of an equation, this is equal to #DeltaG^@=DeltaH^@-TDeltaS^@#; and this equation governs the spontaneity of ALL chemical change, because......
#Delta G^@=-RTlnK_"eq"=DeltaH^@-TDeltaS^@#

For your chemical reaction that represents the dissolution of salt, we write,

#NaCl(s) rightleftharpoonsNa^(+)(aq) + Cl^(-)(aq)#.
The process, is indeed slightly endothermic, in that we have to input energy to break the strong electrostatic bonds that persist between positive and negative ions throughout the entire ionic lattice. Neverthless, because #"entropy change, "DeltaS^@,# is manifestly POSITIVE for this reaction, i.e. the aquated ions have more statistical probability for disorder, #Delta G^@# is NEGATIVE, and thus this reaction is spontaneous as written.

Capisce?

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Answer 2

The reaction occurs because it involves the breaking of the ionic bonds in sodium chloride, allowing the sodium and chloride ions to dissolve in water. This process requires energy, making the reaction slightly endothermic.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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