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We take Nacl and dissolve it in water. There is formation of $Na^+$ and $Cl^-$ gaseous ions along with 2H+ and $Cl^{2-}$ aqueous ions.

Then , Na+ is attracted towards $Cl^{2-}$ and 2H+ is attracted towards $Cl^-$ ions.

Energy required by water molecules to separate the NaCl molecules is knows as Lattice enthalpy.

Energy required to form aqueous NaCl molecule is called hydration enthalpy.

My questions are:

  1. Who is the one that converts gaseous ions of NaCl to aqueous ions?

  2. During the dissolution of NaCl, why is there no formation of solid ions first but directly, it states that gaseous ions of NaCl are formed?

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Fred
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S.M.T
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    Is this an engineering question? Sounds like physics or chemistry SE. – DKNguyen Jul 09 '21 at 13:40
  • @DKNguyen Yes. Engineering thermodynamics. More at a basic level but I am having trouble in understanding it, – S.M.T Jul 09 '21 at 14:37
  • I've never heard of ions being described as solid, liquid, or gas. Also, what "states that gaseous ions of NaCl are formed ?" Are you referring to a source that you can provide? – J. Ari Jul 09 '21 at 16:06
  • @J.Ari Nor I. OP might have in mind that chlorine is a gas at ATP so maybe should make "gaseous ions" whereas sodium is a solid at ATP so maybe should make "solid ions" and is wondering how they become "liquid ions" when dissolved in water. In which case this question seems based on false premises. – DKNguyen Jul 09 '21 at 16:52
  • @DKNguyen I’ll add a photo or link to edit, – S.M.T Jul 09 '21 at 17:02
  • @J.Ari It is what I read I have written and same on what I have confusion about. – S.M.T Jul 09 '21 at 17:06
  • Yeah, this is definitely a chemistry or physics SE. – DKNguyen Jul 09 '21 at 17:22
  • @SrijanM.T I think you should find another source that describes the solvation process. The use of gaseous and aqueous descriptors is more trouble than helpful in explaining solvation. https://chem.libretexts.org/Courses/University_of_Arkansas_Little_Rock/Chem_1403%3A_General_Chemistry_2/Text/13%3A_Solutions/13.02%3A__Solvation_Processes – J. Ari Jul 09 '21 at 20:07
  • I have solved the Q. I will post an answer in some time. – S.M.T Jul 10 '21 at 06:11
  • gas ions exist - you need then to do mass spectrometry. Ionization methods is a whole niche tech area if it's own, with meaningful commercial significance. Solid ions, I think, you're looking at crystal lattice stuff – Pete W Jul 10 '21 at 12:58
  • @DKNguyen - think Cl- ... conceptually, start with a Cl and add an electron. (really, Cl2 and zap it hard with something...) ...or add a proton to something, but usually with somewhat bigger molecules – Pete W Jul 10 '21 at 13:02

1 Answers1

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We define reactions uniquely depending on the reactants and products. Here are examples related to your question.

Formation: Na(s) + (1/2)Cl$_2$(g) $\rightarrow$ NaCl(s)

Lattice Formation: Na$^+$(g) + Cl$^-$(g) $\rightarrow$ NaCl(s)

Solution: NaCl(s) $\rightarrow$ NaCl(aq)

Hydration: Na$^+$(g) $\rightarrow$ Na$^+$(aq)

Atomization: Na(s) $\rightarrow$ Na(g)

A significant observation here is that the STATE of the reactants and products is also required because it is a unique identifier.

As to your questions ...

  1. Who is the one that converts ...

We can convert NaCl(s) to gaseous ions experimentally through processes that may involve multiple steps, including vaporization and ionization.

  1. During the dissolution of NaCl(s), why is there no formation of solid ions first but directly, it states that gaseous ions of NaCl are formed?

The experimental dissolution of NaCl(s) does not involve formation of gaseous ions. It involves formation and solvation of aqueous ions. The two steps (dissolution and solvation) are often not easily separated.

What you refer to is the case where we imagine the dissolution of NaCl(s) happening through a set of steps that include the formation of gaseous ions. The process to combine reaction steps that go from a given set of reactants to a given set of products is formalized in what is called a Born-Haber cycle. This example demonstrates how some of the above reactions fit into a Born-Haber cycle diagram for NaCl(s).

Just because we imagine a reaction path on the Born-Haber cycle does not mean that the reaction occurs experimentally. Indeed, one power to the Born-Haber cycle is to back-calculate an energy for a reaction that does not occur experimentally but that has significant theoretical utility as a building block to obtain other values.

Jeffrey J Weimer
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  • Perfect. Thank you very much – S.M.T Jul 11 '21 at 14:30
  • So this is talking about a model right? Where in this specific instance, only the inputs and outputs can be verified directly but the way the internal bits and pieces can't be? Instead, the exact workings of the internal bits and pieces are confirmed more directly through other tangential processes and the results of those have proven accurate when applied to this scenario? – DKNguyen Jul 11 '21 at 18:33
  • @DKNguyen I believe you are asking whether the reactions in a Born-Haber cycle are required to be [elemental steps](https://opentextbc.ca/chemistry/chapter/12-6-reaction-mechanisms/). The answer is no. – Jeffrey J Weimer Jul 11 '21 at 20:29