Write the equation for the equilibrium that exists when nitrous acid and sodium acetate are placed in solution together (do not include spectator ions). Using published values for the Ka of nitrous acid and of acetic acid, determine the numerical value of the equilibrium constant for that equilibrium.
HNO2 + Ac^- ==> HAc + NO2^-
Keq = [(HAc)(NO2^-)/(HNO2)(Ac^-)]
If you multiply that expression by (H^+)/(H^+) you can see that it is KaHNO2/KaHAc.
Substitute Ka HNO2/Ka HAc and calculate Keq.
To write the equation for the equilibrium between nitrous acid (HNO2) and sodium acetate (NaC2H3O2), we first need to understand the dissociation reactions of each compound in water.
Nitrous acid (HNO2) is a weak acid that dissociates as follows:
HNO2 ⇌ H+ + NO2-
On the other hand, sodium acetate (NaC2H3O2) is a salt that completely dissociates into its constituent ions in water:
NaC2H3O2 → Na+ + C2H3O2-
When these two compounds are mixed in solution, the hydrogen ion (H+) from nitrous acid can react with the acetate ion (C2H3O2-) to form acetic acid (HC2H3O2). This reaction can be represented as follows:
H+ + C2H3O2- ⇌ HC2H3O2
Now we can combine the above reactions to represent the overall equilibrium between nitrous acid and sodium acetate:
HNO2 + NaC2H3O2 ⇌ HC2H3O2 + Na+ + NO2-
This equation represents the equilibrium between the reactants (HNO2 and NaC2H3O2) and the products (HC2H3O2, Na+, and NO2-).
To determine the numerical value of the equilibrium constant (K) for this reaction, we can use the expression:
K = [HC2H3O2] / ([HNO2] * [NaC2H3O2])
The concentrations of the species involved in the equilibrium are denoted by square brackets ([]). To calculate the equilibrium constant, you would need the concentrations of HC2H3O2, HNO2, and NaC2H3O2 at equilibrium. These concentrations can be determined experimentally or provided in the question.
Once the equilibrium concentrations are known, substitute these values into the equation for K to calculate the numerical value of the equilibrium constant.