In which of the following pairs of ionic compounds are both members of the pair soluble in water?

a.AgNO3 and AgCl
b.LiOH and Li2SO4
c.PbSO4 and BaCO3
d.NH4I and Sn3(PO4)2

To determine whether a pair of ionic compounds are soluble in water, we need to refer to the solubility rules for ionic compounds. Here's how you can apply these rules to find the correct answer:

a. AgNO3 and AgCl:
According to the solubility rules, nitrates (NO3-) are generally soluble in water, and chlorides (Cl-) are soluble except for AgCl, PbCl2, and Hg2Cl2. Since AgNO3 is soluble and AgCl is slightly soluble (forming a precipitate in water), this pair is not soluble in water.

b. LiOH and Li2SO4:
According to the solubility rules, hydroxides (OH-) are generally only slightly soluble except for alkali metals (Group 1A) and ammonium (NH4+). Therefore, LiOH is soluble in water. Sulfates (SO4^2-) are generally soluble, so Li2SO4 is also soluble in water. This pair is soluble in water.

c. PbSO4 and BaCO3:
According to the solubility rules, sulfates (SO4^2-) are generally soluble, but PbSO4 is one of the exceptions. It is only slightly soluble and forms a precipitate in water. Carbonates (CO3^2-), on the other hand, are generally insoluble except for alkali metals (Group 1A) and ammonium. Therefore, BaCO3 is slightly soluble. This pair is not soluble in water.

d. NH4I and Sn3(PO4)2:
According to the solubility rules, iodides (I-) are generally soluble except for heavy metals such as lead (Pb^2+), silver (Ag+), and mercury (Hg2^2+). Hence, NH4I is soluble in water. Phosphates (PO4^3-), however, are generally insoluble except for alkali metals (Group 1A) and ammonium. Thus, Sn3(PO4)2 is insoluble in water. This pair is not soluble in water.

To summarize the results:
a. AgNO3 and AgCl: Not soluble in water.
b. LiOH and Li2SO4: Soluble in water.
c. PbSO4 and BaCO3: Not soluble in water.
d. NH4I and Sn3(PO4)2: Not soluble in water.

Therefore, the correct answer is option b. LiOH and Li2SO4

To determine the solubility of ionic compounds in water, we need to refer to solubility rules. Here are the rules:

1. All nitrates (NO3-) are soluble.
2. All alkali metal (Group 1) and ammonium (NH4+) compounds are soluble.
3. Most chlorides (Cl-) are soluble, except for those of silver (Ag+), lead (Pb2+), and mercury (Hg2 2+).
4. Most sulfates (SO4 2-) are soluble, except for those of calcium (Ca2+), strontium (Sr2+), barium (Ba2+), lead (Pb2+), and silver (Ag+).
5. Most carbonates (CO3 2-) and phosphates (PO4 3-) are insoluble, except for those of alkali metals (Group 1) and ammonium (NH4+).

Now let's go through each pair of compounds:

a. AgNO3 and AgCl
AgNO3 is soluble because it is a nitrate (solubility rule #1).
AgCl is insoluble because it is a chloride of silver (solubility rule #3).
So, only AgNO3 is soluble.

b. LiOH and Li2SO4
LiOH is soluble because it is an alkali metal (Group 1) compound (solubility rule #2).
Li2SO4 is soluble because it is an alkali metal (Group 1) compound (solubility rule #2).
So, both LiOH and Li2SO4 are soluble.

c. PbSO4 and BaCO3
PbSO4 is insoluble because it is a sulfate of lead (solubility rule #4).
BaCO3 is insoluble because it is a carbonate (solubility rule #5).
So, neither PbSO4 nor BaCO3 is soluble.

d. NH4I and Sn3(PO4)2
NH4I is soluble because it is an ammonium compound (solubility rule #2).
Sn3(PO4)2 is insoluble because it is a phosphate (solubility rule #5).
So, only NH4I is soluble.

Therefore, the answer is option b. Both LiOH and Li2SO4 are soluble in water.

You need to know the solubility rules. Here is a simplified set. I shall be happy to check your answer.

http://www.csudh.edu/oliver/chemdata/solrules.htm