Which salt would have its solubility most affected by pH change?

[DSNCSUN]

a. CuCl
b. AgBr
c. BaF2
d. AgI

The answer is C. The way I am thinking about it is that if pH is lowered and the F of BaF2 reacts with H+ ions we get a weak acid which cannot completely dissociate resulting in a change in pH. While all the other options have a component leading to a strong acid. HOWEVER, if the pH is made basic and something like CuCl reacts with -OH then you get an insoluble hydroxide which would also change solubility??? Confused here, maybe have wrong logic. need help please!

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[DAT Destroyer]

a. CuCl
b. AgBr
c. BaF2
d. AgI

The answer is C. The way I am thinking about it is that if pH is lowered and the F of BaF2 reacts with H+ ions we get a weak acid which cannot completely dissociate resulting in a change in pH. While all the other options have a component leading to a strong acid. HOWEVER, if the pH is made basic and something like CuCl reacts with -OH then you get an insoluble hydroxide which would also change solubility??? Confused here, maybe have wrong logic. need help please!

Acids will react with 5 ions; CN- OH- , F-, S2-, CO32- and CH3CO2-
When these ions are produced in the solution, they will combine with H+ ions coming from the acid. This will take ions out the the solution forcing the salt to produce more Fluoride ions, via Le Chatelier's principle.
Since more Fluorine will be taking out of the reaction, more BaF2 will dissolve.

Hope this helps.

 

[DSNCSUN]

Acids will react with 5 ions; CN- OH- , F-, S2-, CO32- and CH3CO2-
When these ions are produced in the solution, they will combine with H+ ions coming from the acid. This will take ions out the the solution forcing the salt to produce more Fluoride ions, via Le Chatelier's principle.
Since more Fluorine will be taking out of the reaction, more BaF2 will dissolve.

Hope this helps.

Thank you for the help, I was wondering can we make it basic instead of acidic? What would happen then? Or does pH change talking about H+ ions only. confused there.

 

[DAT Destroyer]

Thank you for the help, I was wondering can we make it basic instead of acidic? What would happen then? Or does pH change talking about H+ ions only. confused there.

No......basicity is different. When dealing with pH, we are dealing with Hydronium ions, namely H+ ions.

 

[DSNCSUN]

No......basicity is different. When dealing with pH, we are dealing with Hydronium ions, namely H+ ions.

thank you!

 

[starsbeneathme]

No......basicity is different. When dealing with pH, we are dealing with Hydronium ions, namely H+ ions.

If base was added to a solution of BaF2, how would this affect the pH of the solution and the solubility of the salt?

 

[Lnguyen7]

BaF2 is basic. Adding base will increase pH and decrease the solubility.

 

[starsbeneathme]

BaF2 is basic. Adding base will increase pH and decrease the solubility.

thanks!

if focusing on an acidic salt, adding base would increase pH and increase solubility?

 

[Lnguyen7]

Anytime you add a base, the pH will always increase. That's what bases do.
Yes, acidic salts will be more soluble in basic environment and basic salts will be more soluble in acidic environment.

 

[starsbeneathme]

Anytime you add a base, the pH will always increase. That's what bases do.
Yes, acidic salts will be more soluble in basic environment and basic salts will be more soluble in acidic environment.

thanks

 

[Charles_Darwin]

Acids will react with 5 ions; CN- OH- , F-, S2-, CO32- and CH3CO2-
When these ions are produced in the solution, they will combine with H+ ions coming from the acid. This will take ions out the the solution forcing the salt to produce more Fluoride ions, via Le Chatelier's principle.
Since more Fluorine will be taking out of the reaction, more BaF2 will dissolve.

Hope this helps.

Also noticed I had this question open in my book! They way I thought of it was, ions A/b/d all were weak bases, except for c, since F- is a good base. Therefore it'd most efficiently dissolve in water.

 

[fayevalentine]

Commenting so I can review this again

 

[dl2501]

Acids will react with 5 ions; CN- OH- , F-, S2-, CO32- and CH3CO2-
When these ions are produced in the solution, they will combine with H+ ions coming from the acid. This will take ions out the the solution forcing the salt to produce more Fluoride ions, via Le Chatelier's principle.
Since more Fluorine will be taking out of the reaction, more BaF2 will dissolve.

Hope this helps.

Dr. Romano,

For this question, answer choice B) AgBr is not considered of the solubility rule... would that be the correct assumption?

Thank you in advance!