Pb(NO3)2(aq) 2 x 10-3 M
Na2SO4(aq) 2 x 10-3 M
Pb(NO3)2(aq) + NaSO4(aq) → PbSO4(s)+ 2NaNO3(aq)
a) What are the concentrations of each ion within this solution?
b) If 1L of each solution is mixed; will a precipitate form? why?
concn each ion, if no ppt forms, given in the problem.
Will a ppt form? Calculate the ion product for PbSO4 and compare with Ksp.
To determine the concentrations of each ion in the solution and whether a precipitate will form, we need to use the concept of stoichiometry and solubility rules.
a) Concentrations of each ion in the solution:
The compound Pb(NO3)2 dissociates into ions when it is dissolved in water. The cations in Pb(NO3)2 are Pb2+ and the anions are NO3-. Similarly, Na2SO4 dissociates into Na+ and SO42- ions in the aqueous solution.
So, for Pb(NO3)2:
- Concentration of Pb2+ ion = 2 x 10-3 M (given)
- Concentration of NO3- ion = 2 x 10-3 M (derived from Pb(NO3)2)
And for Na2SO4:
- Concentration of Na+ ion = 2 x 10-3 M (given)
- Concentration of SO42- ion = 2 x 10-3 M (derived from Na2SO4)
b) Precipitate formation:
To determine if a precipitate will form, we need to examine the solubility of the resulting compound, PbSO4. According to the solubility rules, most sulfates are soluble in water except for a few exceptions, like PbSO4.
PbSO4 is classified as an insoluble salt and is considered a precipitate when formed in an aqueous solution. When Pb2+ and SO42- ions combine, they form an insoluble compound, PbSO4, which appears as a solid in the reaction.
Since both solutions have equal concentrations of 2 x 10-3 M, a reaction between them will result in their complete consumption, thereby forming PbSO4 and 2NaNO3.
Therefore, in this case, a precipitate of PbSO4 will form due to its low solubility, while 2NaNO3 will remain in the aqueous solution.