what one is the Most Soluble compound

1) CuS, Ksp = 1.27 x10^-36
2) PbS, Ksp = 9.04 x 10^-29
3) AgCl,Ksp = 1.77 X 10^-10
4) AgI, Ksp = 8.51 x 10^17
5) Not enough information.
My book states that AgCl is insoluble in water and so are MOST phosphates and Sufides, and I am thinking that AgI is also non soluable, so the answer is Not enough info?

Here is a simplified set of solubility rules.

http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
If you will look carefully, ALL (that's ALL) of the five choices are insoluble in water. Therefore, the answer to the problem is not WHICH is insoluble. All of them are insoluble. Look at the Ksp values. The smallest value will be the least soluble, the largest value will be the most soluble.
Caution: The only time you can compare the solubilities strictly with Ksp is when all of the compounds are the same ratio of + and - ions, as they are in this case. AgCl is 1:1; CuS is 1:1, etc. For example, you could not compare directly if you had AgCl and Ag2CrO4 since AgCl is 1:1 and Ag2CrO4 is 2:1. In a case where they are not the same ratio you must calculate the solubility of each to know which is more or less soluble than another salt.

Thank you Dr Bob!! I was thinking most of the same that you said, even about the 1:1 ratio, and my book had most of the actual compounds stated about being insoluble IN WATER. I was just was trying to figure it all out and make sense of the values and the insoluble compounds, thinking that maybe with the largest value one, being one of those "times" when the MOST did not come into play.

The correct answer is 5) Not enough information. The solubility of a compound is determined by its Ksp value. Ksp represents the solubility product constant and indicates the extent to which a compound can dissolve in water. The higher the Ksp value, the more soluble the compound.

In this case, you have provided the Ksp values for CuS, PbS, AgCl, and AgI. However, without information about the specific solubility of these compounds (i.e., if they exceed their Ksp values), we cannot determine which one is the most soluble. Therefore, the answer is not enough information.

To determine which compound is the most soluble, we can compare their solubility product constants (Ksp) values. The Ksp value represents the equilibrium constant for the dissolution of a compound in water.

In this case, we have the following values:

1) CuS, Ksp = 1.27 x 10^-36
2) PbS, Ksp = 9.04 x 10^-29
3) AgCl, Ksp = 1.77 x 10^-10
4) AgI, Ksp = 8.51 x 10^17
5) Not enough information.

Based on the given Ksp values, we can see that AgI has the highest Ksp value, indicating that it is the most soluble compound among the options provided. Therefore, the correct answer is 4) AgI.

It is important to note that while AgCl is generally considered insoluble, it does have a finite solubility, as indicated by its Ksp value. Similarly, AgI is considered less soluble than AgCl. However, without further information, we cannot make a conclusive comparison between the solubilities of AgCl and AgI.