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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: MangoPlant on May 25, 2013, 07:47:33 PM

Title: Is my reasoning correct? [Solubility]
Post by: MangoPlant on May 25, 2013, 07:47:33 PM

Hello. I was just wondering if someone could confirm whether my reasoning is correct or point to some flaws?

Given that PbCO₃  is less soluble than PbI₂, and that precipitates are formed when either CO₃^2- or I^- ions are added to a aqueous solution of Pb²⁺, what would happen if CO₃^2- ions were added to a mixture of PbI₂ crystals in a large beaker of water?

My reasoning: Since PbCO₃ is less soluble than PbI₂ the CO₃^2- ions would react with whatever few Pb²⁺ are formed from the very little dissociation of PbI₂ and precipitate out as PbCO₃, which will shift the equilibrium of PbI₂ to the right (into it's dissociated ions), and if enough CO₃^2- ions are added eventually the equilibrium will keep shifting and all of the PbI₂ will disappear.

Title: Re: Is my reasoning correct? [Solubility]
Post by: Corribus on May 25, 2013, 08:47:05 PM

Your general reasoning seems sound. 

Title: Re: Is my reasoning correct? [Solubility]
Post by: 408 on May 25, 2013, 11:12:57 PM

This is exactly what will happen.

Title: Re: Is my reasoning correct? [Solubility]
Post by: MangoPlant on May 26, 2013, 05:29:26 PM

Thanks Corribus and 408.  :)