For 0.10 M ZnCl2 and 0.10 M KAl(SO4)2, find:?
a) spectator ions (if any)
b) ions expected to hydrolyze (if any)
c) net ionic equation for hydrolysis
d) expression for equilibrium constant (Ka or Kb)
e) value of Ka or Kb
My answers are:
a) Cl- ; K+ ; SO4^2-
b) Zn+ ; Al3+
please help me c); d); and e)
Dr Bob's response says the Zn and Al should be added to a) the spectator ions, and also be answer to b) the ions which will hydrolyze. How can they be both?
c) Net ionic equation for hydrolysis:
Zn2+ + 2OH- -> Zn(OH)2
d) Expression for equilibrium constant (Ka or Kb):
Ka = [Zn(OH)2] / ([Zn2+] * [OH-]^2)
e) Value of Ka:
The value of Ka would have to be calculated based on experimental data or provided by a reliable source. It cannot be determined just knowing the concentration of the reactants.
To find the net ionic equation for hydrolysis, expression for the equilibrium constant, and its value, we need to understand the properties of the compounds involved. Let's break it down step by step.
a) Spectator ions are ions that do not actively participate in the chemical reaction. They remain unchanged throughout the reaction. In this case, since we have ZnCl2 and KAl(SO4)2, the spectator ions are Cl- (from ZnCl2) and K+ and SO4^2- (from KAl(SO4)2). Therefore, the spectator ions are Cl-, K+, and SO4^2-.
b) Ions expected to hydrolyze are the ones that will react with water to produce either H+ (acidic hydrolysis) or OH- (basic hydrolysis). In this case, only the cations Zn+ (from ZnCl2) and Al3+ (from KAl(SO4)2) are expected to hydrolyze.
c) To write the net ionic equation for hydrolysis, we need to consider the ions that are expected to hydrolyze and the water molecules. Hydrolysis of Zn+ produces Zn(OH)2 and hydrolysis of Al3+ produces Al(OH)3. The reaction can be written as:
Zn+ (aq) + 2H2O (l) --> Zn(OH)2 (s) + 2H+ (aq)
Al3+ (aq) + 3H2O (l) --> Al(OH)3 (s) + 3H+ (aq)
Note: I've included the state symbols (aq for aqueous and l for liquid) and (s for solid) to indicate the physical state of the species involved.
d) The expression for the equilibrium constant (K) for the hydrolysis reaction can be written as:
K = [Zn(OH)2] * [H+]^2 / [Zn+] * [H2O]^2
K = [Al(OH)3] * [H+]^3 / [Al3+] * [H2O]^3
e) To find the value of Ka or Kb, we need additional information such as the solubility product constant (Ksp) of Zn(OH)2 and Al(OH)3 or any other relevant information provided in the question. The Ka or Kb values cannot be determined without this additional data.
Therefore, based on the information provided, we can find the spectator ions and ions expected to hydrolyze, write the net ionic equation for hydrolysis, and express the equilibrium constant, but the exact value of Ka or Kb cannot be determined without further information.
a) needs work. What you have plus Zn^+2 and Al^+3.
b) is ok.
Here is a site that explains the hydrolysis of metal hydrate ions (which you have with Al(H2O)6^+3 and Zn hydrates). Set up an ICE chart for these two which should allow you to calculate both H^+ and Ka. There is no hydrolysis for the anions UNLESS you want to get fancy and go through the SO4^-2 to produce HSO4^-.