which of the following salts do you expect to have the lowest water solubility?
a...SrF2
b...Rb2O
c...Ga2O3
d...CsNO3
All the numbers are subscripts
Correct
Nitrates are soluble so I would cross off d.
Rb2O is similar to Na2O, Li2O, etc and they are quite soluble (forming bases).
SrF2 is relatively insoluble (similar to CaF2 etc) so a possibility.
Ga2O3 is similar to Al2O3. We KNOW Al2O3 is almost completely insoluble. I would go with Ga2O3.
To determine which salt would have the lowest water solubility among SrF2, Rb2O, Ga2O3, and CsNO3, we need to consider the solubility rules.
One of the general solubility rules states that salts containing Group 1 cations (such as Sr2+, Rb+, and Cs+) and the ammonium ion (NH4+) are soluble in water. That means salts containing these cations tend to dissociate and form aqueous solutions.
On the other hand, salts containing the anions fluoride (F-), oxide (O2-), and nitrate (NO3-) are generally soluble in water.
Let's analyze the options:
a) SrF2: This salt contains the cation Sr2+ and the anion F-. According to the solubility rules, this salt is expected to be soluble in water.
b) Rb2O: This salt contains the cation Rb+ and the anion O2-. Since salts containing Group 1 cations such as Rb+ are soluble in water, and oxides are generally soluble, we can expect this salt to be soluble.
c) Ga2O3: This salt contains the cation Ga3+ and the anion O2-. It is important to note that Ga3+ is not a Group 1 cation, so the solubility of this salt cannot be determined solely based on the solubility rules. However, metal oxides like Ga2O3 are generally not very soluble in water, making it likely to have lower water solubility compared to the other options.
d) CsNO3: This salt contains the cation Cs+ and the anion NO3-. According to the solubility rules, salts containing Group 1 cations like Cs+ and nitrate ions (NO3-) are soluble in water. Hence, it is expected to be soluble.
Based on the analysis, the salt with the lowest water solubility among the given options is Ga2O3 (option c).