Which of the following pairs of compounds will give a precipitate in a diluted solution?**
a) Cu(NO3)2 and Na2CO3
b) KNO3 and NaCl
c) MgCl2 and Ba(NO3)2
d) NH4Cl and Al2(SO4)3
A solution contains I-, Br- and OH- ions. If Ag+ is added, what will the precipitate(s) be?
a) AgOH
b) AgI and AgBr
c) AgOH and AgBr
d) AgOH, AgI and AgBr
2. d
To determine which pairs of compounds will give a precipitate in a diluted solution and what precipitate(s) will form when Ag+ is added to a solution containing I-, Br-, and OH- ions, we will first need to identify the solubility rules.
For the first question:
a) Cu(NO3)2 and Na2CO3
Using the solubility rules, we can determine that Cu(NO3)2 is soluble and Na2CO3 is soluble except with Group 1 cations and ammonium. Therefore, there will be no precipitate formed.
b) KNO3 and NaCl
Both KNO3 and NaCl are soluble according to the solubility rules. Therefore, there will be no precipitate formed.
c) MgCl2 and Ba(NO3)2
MgCl2 is soluble according to the solubility rules, while Ba(NO3)2 is also soluble except with sulfate and Group 1 cations. Therefore, there will be no precipitate formed.
d) NH4Cl and Al2(SO4)3
NH4Cl is soluble according to the solubility rules. Al2(SO4)3 is soluble except with Group 1 cations and ammonium. Therefore, there will be no precipitate formed.
Based on the solubility rules, none of the pairs of compounds will give a precipitate in a diluted solution.
For the second question:
The solubility rules indicate that AgOH is insoluble, AgI is slightly soluble, and AgBr is slightly soluble. When Ag+ is added to a solution containing I-, Br-, and OH- ions, the following precipitates will form:
a) AgOH does not precipitate.
b) AgI and AgBr will slightly precipitate.
c) AgOH will precipitate, but AgBr will slightly precipitate.
d) AgOH, AgI, and AgBr will all precipitate.
Based on the solubility rules, the correct answer is:
b) AgI and AgBr
These are the precipitates that will form when Ag+ is added to the solution containing I-, Br-, and OH- ions.
To determine which pairs of compounds will form a precipitate in a diluted solution, we need to cross-reference the solubility rules for common ionic compounds.
a) Cu(NO3)2 and Na2CO3:
- Cu(NO3)2 is a soluble salt since most nitrates are soluble.
- Na2CO3 is also soluble since most carbonates are soluble.
Since both compounds are soluble, there will be no precipitation.
b) KNO3 and NaCl:
- KNO3 is soluble because most nitrates are soluble.
- NaCl is soluble because most chlorides are soluble.
Again, both compounds are soluble, so there will be no precipitation.
c) MgCl2 and Ba(NO3)2:
- MgCl2 is soluble because most chlorides are soluble.
- Ba(NO3)2 is soluble because most nitrates are soluble.
Since both compounds are soluble, no precipitate will form.
d) NH4Cl and Al2(SO4)3:
- NH4Cl is soluble because most chlorides are soluble.
- Al2(SO4)3 is soluble because most sulfates are soluble.
As both compounds are soluble, there will be no precipitation.
Thus, none of the pairs of compounds in the options given will form a precipitate in a diluted solution.
Now, let's move on to the second question:
If a solution contains I-, Br-, and OH- ions, and Ag+ is added, we need to determine which of the resulting compounds will precipitate. To do this, we need to refer to the solubility rules again.
a) AgOH: AgOH is insoluble, so it will form a precipitate.
b) AgI and AgBr: AgI is soluble, but AgBr is insoluble. Therefore, only AgBr will form a precipitate.
c) AgOH and AgBr: As mentioned earlier, AgOH is insoluble, and AgBr is also insoluble. Therefore, both compounds will precipitate.
d) AgOH, AgI, and AgBr: AgI is soluble, so we only have AgOH and AgBr as insoluble compounds. Therefore, both compounds will form precipitates.
In summary, if Ag+ is added to a solution containing I-, Br-, and OH- ions, the precipitates formed will be AgOH, AgBr, and AgI (option d).
You need to know the solubility rules.
Here is a simplified set of rules.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html