Why Do Ag+ Ions Replace Na+ Ions in NaCl Solution?

  • Thread starter Thread starter HorseBox
  • Start date Start date
  • Tags Tags
    Ions
AI Thread Summary
When NaCl is mixed with AgNO3, a white precipitate of AgCl forms due to the reaction between Ag+ ions and Cl- ions. This occurs because AgCl is relatively insoluble in water, shifting the equilibrium towards the formation of the solid precipitate rather than allowing the ions to remain dissolved. The discussion clarifies that the formation of the precipitate is not primarily influenced by electronegativity differences between Cl- and NO3- or between Ag+ and Na+ ions. Instead, the solubility characteristics of AgCl dictate the reaction dynamics, leading to the precipitation rather than a reversible dissolution.
HorseBox
Messages
25
Reaction score
0
Lets say I have a solution of NaCl and decide to add some AgNO3. I know a white precipitate will form so obviously some Ag+ ions have dropped their NO3- counterparts and combined with Cl- ions instead. Why does this happen? Is it all to do with electronegativity? Is it a simple matter of Cl- anions being more electronegative than NO3- anions and Ag+ cations being more electropositive than Na+ cations?
 
Chemistry news on Phys.org
When these things dissolve in water, you have an equilibrium, e.g.:
NaCl <--> Na+ + Cl-
Salt is quite soluble so obviously that equilibrium is shifted pretty heavily to the right most of the time.

So your dissolved salts are continuously dissolving and reforming, and in different combinations. As it happens, AgCl is relatively insoluble, so the equilibrium:
AgCl <--> Ag+ + Cl-
Is shifted to the left.

So the ions don't go back into solution much. That's what 'insoluble' means.
 
Does electronegatively play a significant role in this?
 
Nope.
 
Thanks a lot.
 
I want to test a humidity sensor with one or more saturated salt solutions. The table salt that I have on hand contains one of two anticaking agents, calcium silicate or sodium aluminosilicate. Will the presence of either of these additives (or iodine for that matter) significantly affect the equilibrium humidity? I searched and all the how-to-do-it guides did not address this question. One research paper I found reported that at 1.5% w/w calcium silicate increased the deliquescent point by...
I'm trying to find a cheap DIY method to etch holes of various shapes through 0.3mm Aluminium sheet using 5-10% Sodium Hydroxide. The idea is to apply a resist to the Aluminium then selectively ablate it off using a diode laser cutter and then dissolve away the Aluminium using Sodium Hydroxide. By cheap I mean resists costing say £20 in small quantities. The Internet has suggested various resists to try including... Enamel paint (only survived seconds in the NaOH!) Acrylic paint (only...
Back
Top