Which solution would CaC2O4 be most soluble in?

Question

Na2C2O4
NaHC2O4
H2C2O4
NaCl
HCl

I due to common ions i think it would be one of the first three and i think it is Na2C2O4 because the other 2 have Hydrogen. Is it Na2C2O4?

No, the common ions work just the other way; CaC2O4 will be less soluble in the first three. It will be most soluble in one of the last two. To prove this point, write the solubility equation for CaC2O4, then the Ksp for CaC2O4, then the solubility equations for the first three. Lastly, apply Le Chatlelier's Principle and the Ksp and you will see that the first three will shift the solubility equation to the left toward the solid CaC2O4 before it dissolves making CaC2O4 less soluble in all three. To pick the one of the last two (NaCl or HCl), do the same thing and you will see which will shift the equilibrium to the right to make CaC2O4 more soluble.

Dear Dr.Bob222
I am studing chemistry in UC i want to know about Whisker.
Thank you
Bahman
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