chem question

[tissy]

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In which of the floolwoing solutions would CaF2 be least soluble?

A. .01MCaCl2
B. .02MCaCl2
C. .01MNaF
D. .02MNaF
E. .02MNaCL

Please explain

Thanks

 

[tissy]

Here's another one:

Which gives the most basic solution when dissolved in water?

A. H3PO4
B. NaH2PO4
C. P2O5
D. NaNO3
E. P2O5Na3PO4

Please help?

 

[GoDucks69]

In which of the floolwoing solutions would CaF2 be least soluble?

A. .01MCaCl2
B. .02MCaCl2
C. .01MNaF
D. .02MNaF
E. .02MNaCL

Please explain

Thanks

I would say the answer is D because of the common ion effect. If a lot of F- ions are floating around it would be harder to dissolve CaF2 in that solution. I was caught up between C and D and I figured that more F- ions would make it more difficult to dissolve the compound but I could be wrong.

 

[Notoriousjae]

Here's another one:

Which gives the most basic solution when dissolved in water?

A. H3PO4
B. NaH2PO4
C. P2O5
D. NaNO3
E. P2O5Na3PO4

Please help?

I would say E

 

[Dr. juju]

I would say the answer is D because of the common ion effect. If a lot of F- ions are floating around it would be harder to dissolve CaF2 in that solution. I was caught up between C and D and I figured that more F- ions would make it more difficult to dissolve the compound but I could be wrong.

I was also choosing between B and D but then how can you eliminate B? it has a lot of Ca for common ion!!!

 

[Dr. juju]

Here's another one:

Which gives the most basic solution when dissolved in water?

A. H3PO4
B. NaH2PO4
C. P2O5
D. NaNO3
E. P2O5Na3PO4

Please help?

it'd say it's D. NaOH is a very strong base, compared to the conj base of a strong base. Also NO3 is a strong organic base ( i think).

 

[How Sleepy??!!]

The answer to your first question is D. Due to the common ion effect, and since Fluorine would be in the largest quantity when aqueous, a solution with the highest concentration of F- ion would shift the reaction to the left, decreasing the solubility.

The answer to your second question would be B. While choice D is tempting, when placed in water it would produce a strong base and a strong acid - resulting in a neutral solution. In B however, we would produce a strong base (NaOH) and a weak acid - resulting in an overall basic solution.

Hope this is helpful.