the common ion effect. saturated sodium chloride solution contains solid nacl in equilibrium with...
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![Page 1: The common ion effect. Saturated sodium chloride solution contains solid NaCl in equilibrium with the aqueous ions: NaCl(s) Na + (aq) + Cl – (aq) We know](https://reader030.vdocuments.us/reader030/viewer/2022033015/56649d025503460f949d5302/html5/thumbnails/1.jpg)
The common ion effect
![Page 2: The common ion effect. Saturated sodium chloride solution contains solid NaCl in equilibrium with the aqueous ions: NaCl(s) Na + (aq) + Cl – (aq) We know](https://reader030.vdocuments.us/reader030/viewer/2022033015/56649d025503460f949d5302/html5/thumbnails/2.jpg)
Saturated sodium chloride solution contains solid NaCl in equilibrium with the aqueous ions:NaCl(s) Na+(aq) + Cl–
(aq)
We know this sodium chloride solution is saturated because there are crystals of solid NaCl at the bottom of the bottle.
![Page 3: The common ion effect. Saturated sodium chloride solution contains solid NaCl in equilibrium with the aqueous ions: NaCl(s) Na + (aq) + Cl – (aq) We know](https://reader030.vdocuments.us/reader030/viewer/2022033015/56649d025503460f949d5302/html5/thumbnails/3.jpg)
Some of the saturated solution is poured into a test tube.
Since this liquid is clear we know that all the ions are in solution.
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Concentrated hydrochloric acid contains a high concentration of Cl–(aq).
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Some of the colourless conc HCl solution is put in a dropper, ready to add to the saturated salt solution.
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A single drop of HCl falls into the saturated solution and immediately forms crystals of NaCl.
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It’s more impressive if we give it a good squirt…
![Page 8: The common ion effect. Saturated sodium chloride solution contains solid NaCl in equilibrium with the aqueous ions: NaCl(s) Na + (aq) + Cl – (aq) We know](https://reader030.vdocuments.us/reader030/viewer/2022033015/56649d025503460f949d5302/html5/thumbnails/8.jpg)
Saturated NaCl contains about 6 mol L–1 of NaCl.
[Na+] = 6 mol L–1; [Cl–] = 6 mol L–1
[Na+][Cl–] = Ks = 36
Concentrated HCl is about 11 mol L–1, which significantly increases the concentration of chloride ions.
Since the ionic product, [Na+][Cl–], exceeds the Ks, a precipitate of NaCl(s) forms.The solubility of a compound will decrease in the presence of another compound with a common ion.
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You may have separated soap (sodium stearate) from the mixture of glycerol and unreacted sodium hydroxide by adding saturated salt.