According to the rules of writing ionic equation, only compounds in aqueous state can be split or dissociated into their ions, whereas elements or compounds in solid, liquid or gas state remain as they are. But what about molten sodium chloride which is NaCl(l) in liquid state, isn't it dissociated into ions when melted? So can we split it into its respective ions when writing ionic equations?

  • $\begingroup$ Whose rules? Such a claim should have a specific reference and an explicit quote. I dislike a reference to vague and unknown authority. $\endgroup$ – MaxW May 7 '20 at 4:44
  • $\begingroup$ @MaxW occc.edu/kmbailey/Chem1115Tutorials/Net_Ionic_Eqns.htm I got the information from here, perhaps I phrased it in a wrong way. $\endgroup$ – hao004 May 7 '20 at 5:33
  • $\begingroup$ I think you mostly misunderstood. The webpage starts off with "When aqueous solutions of sodium phosphate and calcium chloride are mixed together..." So that is the context. $\endgroup$ – MaxW May 7 '20 at 5:59
  • $\begingroup$ @MaxW so imagine when molten sodium chloride is one of the reactants which is NaCl (l) right? Can we separate it into its ions when writing the ionic equations? As 3rd point in the link said, "Bring down all compounds with (s), (l) or (g) unchanged." $\endgroup$ – hao004 May 7 '20 at 6:04
  • $\begingroup$ How does molten sodium chloride have anything to do with the context of an aqueous solution of sodium phosphate and calcium chloride? You must be careful not to extrapolate statements beyond their context. // I'd agree that the webpage could use some editing. It is always nice to have several people read something to reduce the possibility of misconceptions in reading. $\endgroup$ – MaxW May 7 '20 at 6:08

The statement, "only compounds in aqueous state can be split or dissociated into their ions," is false in a number of ways.

  1. As you state, molten salts are ionic, and there are room-temperature ionic liquids, such as ethylammonium nitrate , $\ce{(C2H5)NH3+·NO3-}$.
  2. In addition to water, there are other ionic solvents, such as nitromethane, $\ce{CH3NO2}$. Salts in these solvents break up to form ions.
  3. Further, not everything dissolved in water is ionized. Sugar (sucrose), for example, is not ionized.

Yes Sodium and chlorine seperate into their ions. NaCl can turn into sodium ion and chlorine ion when molten. You could seperate it into respective ions if you want to write ionic equations.


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