According to Solubility - Product Constants (Ksp) if the number is high, is it more soluble?

Question

If the ksp number is higher does that make it more or less soluble? Thanks

Ex: BaSO4 Ksp=1.01 x 10^-10
and CaSO4 Ksp=7.1 x 10^-5

Answer 1

Lancenigo di Villorba (TV), Italy

PUBLIC RELATION
Hi, I am a young engineer.
Despite all the regulamentar statements involving my profession, I remain a Chemistry's Lover : I love all the questions interesting Stuff's Metamorphosis, see Chemistry.
I told you about me....and you? Can I ask something about you? Do you know the Pretty Girl in the Photo?

YOUR QUESTION
You may think :"THE GREATER THE STUFF's Ksp, THE GREATER THE STUFF's SOLUBILITY".
IT MAY RUN NOT IN THIS FASHION.
What it is the simplest picture of the argument?
I think to very simple experiments, e.g. the dissolution of a pure chemical compounds in the assigned solvent.
Hence, I may add continuously small doses of the solid stuff in the solvent.....I stop this action when I can see some downstanding bodies at the bottom.
As you thought, different chemical compounds show different solubilities in aqueous media.
I start my discussion speaking about the SOLUBILITY, e.g. the maximum containt of a chemical compound admitted in a specified solvent, that it means the Saturated Concentration : usually chemists refer to Molar Concentrations.
A sketch of the chemical phenomena involved follows

AxBy(s) <---> x A(aq) + y B(aq)

where the AxBy is a chemical compound undergoing ionic dissociation as A and B Ions.
Similarly to other chemical events, I estimate the Activity's Product in the Equilibrium's Conditions

Ksp = |A|^x * |B|^y

since the |AxBy|'s Activity is assumed as the Unity (e.g. it is an unsoluble solid) : I overcame to "Solubilities Product".
Following my reasoning, you understood that the greater Ksp, the greater the |A|eq and |B|eq, the greater the Chemical Compound's Solubility.

CALCULATIONs
I join to treat the case of BaSO4 and CaSO4 :the related dissociation's equilibria follow

BaSO4(s) <---> Ba++(aq) + SO4--(aq)
CaSO4(s) <---> Ca++(aq) + SO4--(aq)

hence the related Solubilities Products are the following ones

Ksp,1 = |Ba++| * |SO4--|
Ksp,2 = |Ca++| * |SO4--|

As you know, I refer to two different and separated experiments ; stoichiometrically speaking, the two Chemical Compounds are simply constituted

|BaSO4| = |Ba++| = |SO4--|
|CaSO4| = |Ca++| = |SO4--|

so I may rearrange the mathematical terms

Ksp,1 = |BaSO4|^2
Ksp,2 = |CaSO4|^2

Concluding, the related solubilities of the two Chemical Compounds in its aqueous solutions

|BaSO4| = (Ksp,1)^0.5 = 1.0E-5 M
|CaSO4| = (Ksp,2)^0.5 = 8.3E-3 M

CONCLUSIONs
THE TREND ON THE MATTER SHOW THAT THE GREATER Ksp, THE GREATER THE STUFF's SOLUBILITY.
WARNING!! YOU CANNOT APPLY THIS STATEMENT...YOU MUST CALCULATE SOLUBILITIES.
Ksp,AgCl = 1.0E-10.........|AgCl| = 1.0E-5 M
Ksp,Ag2CrO4 = 1.0E-12 ......|Ag2CrO4| = 6.2E-5 M
INSTEAD THE LOWEST Ksp's VALUE, Ag2CrO4 IS USUALLY MORE SOLUBLE THAN AgCl, DID YOU THINK?
MOREOVER, I may treat a Chemical Compound constituted ONE OR MORE IONS TAKING PART TO OTHER CHEMICAL PHENOMENA, e.g. ACID-BASE's EQUILIBRIA.

I hope this helps you.

Answer 2

If you can define K, you know the answer. K = [products]/[reactants]. High K = high [products] or low [reactants].

example: A + B = C; if K is higher, then the reaction goes towards more products (C). If A is more soluble in B then you will make more C.