Would you expect PbCl2 to dissolve in dilute HNO3(aq)?
Explain in terms of solubility (Ksp)/equilibrium?
Not appreciably although PbCl2 is not that insoluble.
To determine whether PbCl2 would dissolve in dilute HNO3(aq), we need to examine the solubility (Ksp) and the effect of the HNO3 on the equilibrium.
PbCl2 is a sparingly soluble ionic compound, meaning it has a low solubility in water. When PbCl2 dissolves in water, it dissociates into lead(II) ions (Pb2+) and chloride ions (Cl-). This can be represented by the following equilibrium equation:
PbCl2(s) ⇌ Pb2+(aq) + 2Cl-(aq)
The solubility product constant (Ksp) describes the extent to which an ionic compound dissociates in water. For PbCl2, the Ksp expression is:
Ksp = [Pb2+][Cl-]^2
HNO3(aq), on the other hand, is a strong acid that dissociates completely in water to produce hydrogen ions (H+) and nitrate ions (NO3-):
HNO3(aq) → H+(aq) + NO3-(aq)
When dilute HNO3(aq) is added to PbCl2, the nitrate ions (NO3-) will react with the lead ions (Pb2+), forming the sparingly soluble lead nitrate (Pb(NO3)2) compound:
Pb2+(aq) + 2NO3-(aq) → Pb(NO3)2(s)
Since lead nitrate has a higher solubility than lead chloride, the formation of the Pb(NO3)2 compound will reduce the concentration of Pb2+ ions in solution, shifting the equilibrium to the left. As a result, more solid PbCl2 will precipitate out of solution.
Therefore, we would not expect PbCl2 to dissolve in dilute HNO3(aq) since the nitrate ions in HNO3 react with the lead ions, causing the equilibrium to shift towards the formation of the insoluble lead nitrate compound.
To determine whether PbCl2 would dissolve in dilute HNO3(aq), we need to consider the solubility of PbCl2 and the reaction between PbCl2 and HNO3.
First, let's look at the solubility of PbCl2. The solubility of a compound can be quantified by its solubility product constant, Ksp. Ksp represents the equilibrium constant for the dissociation of the compound into its ions in a saturated solution.
The equation for the dissociation of PbCl2 in water can be written as:
PbCl2(s) ↔ Pb2+(aq) + 2Cl-(aq)
The expression for the solubility product constant is given by:
Ksp = [Pb2+][Cl-]^2
Now, let's consider the reaction between PbCl2 and HNO3. Dilute HNO3(aq) can be represented as:
HNO3(aq) → H+(aq) + NO3-(aq)
When PbCl2 dissolves in dilute HNO3(aq), it would undergo a metathesis reaction with the nitrate ions (NO3-) present:
PbCl2(s) + 2HNO3(aq) → Pb(NO3)2(aq) + 2HCl(aq)
To determine whether PbCl2 would dissolve in dilute HNO3(aq), we need to compare the solubility of PbCl2 (based on its Ksp) with the reaction between PbCl2 and HNO3.
If the Ksp of PbCl2 is higher than the reaction quotient (Q) for the reaction between PbCl2 and HNO3, then PbCl2 will dissolve in dilute HNO3(aq) and form lead(II) nitrate (Pb(NO3)2). If the Ksp is lower than Q, then PbCl2 will not dissolve.
To obtain the Ksp of PbCl2, you may refer to literature or relevant databases. The Ksp value will vary based on temperature, so it's important to consider the temperature conditions for accurate comparison. Once you have the Ksp and the relevant concentrations, you can calculate Q to assess whether PbCl2 will dissolve in dilute HNO3(aq).
In summary, to determine if PbCl2 would dissolve in dilute HNO3(aq), compare the solubility product constant (Ksp) of PbCl2 with the reaction quotient (Q) of the reaction between PbCl2 and HNO3.