Question from AAMC #3 - Question 1

[MD2BeWpg]

I realize I am not supposed to post actual questions from the test. So I'm not.
I understand why the right answer is what it is. But can someone please tell me why they say that PbCl2 forms an aqueous solution in the following reaction?
PbCO3 + 2HCl --> PbCl2 (aq) + CO2 + H2O

Aren't all the halogens soluble EXCEPT with heavy metals and Ag, Pb and Hg???? Shouldn't PbCl2 be a solid????

Please Help!

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[BeatMCAT]

I realize I am not supposed to post actual questions from the test. So I'm not.
I understand why the right answer is what it is. But can someone please tell me why they say that PbCl2 forms an aqueous solution in the following reaction?
PbCO3 + 2HCl --> PbCl2 (aq) + CO2 + H2O

Aren't all the halogens soluble EXCEPT with heavy metals and Ag, Pb and Hg???? Shouldn't PbCl2 be a solid????

Please Help!

Yeah that is true to a certain degree but if I remember correctly PbCl2 is still slightly soluble..that's probably the reason. not 100% sure though

 

[englishtablet]

Pbcl2 is sparingly soluble in acids and bases. However, it is not soluble in H2O. On larger scale, definitely not as soluble as any nitrate.

 

[paul411]

IIRC, insoluble is defined as a solubility of less than 3g per 100mL. So feasibly, you can add PbCl2 to a lot of water (let's say 3g in 10L) and that will be an aqueous solution (homeopathic PbCl2 ). However, I'm not completely sure about this, someone else should verify.