Write an equilibrium expression for each chemical equation involving one or more solid or liquid reactants or products.
HCHO2(aq)+H2O(l)⇌H3O+(aq)+CHO−2(aq)
Use A for [HCHO2], B for [H2O], C for [H3O+], D for [CHO−2].
The equilibrium expression for the given chemical equation is as follows:
K = [C][D] / [A][B]
Where:
[A] represents the concentration of HCHO2 (aq)
[B] represents the concentration of H2O (l)
[C] represents the concentration of H3O+ (aq)
[D] represents the concentration of CHO−2 (aq)
The equilibrium constant "K" is determined by the ratio of the concentrations of the products (C and D) divided by the ratio of the concentrations of the reactants (A and B).
To write the equilibrium expression for the given chemical equation:
HCHO2(aq) + H2O(l) ⇌ H3O+(aq) + CHO−2(aq)
We'll use the concentrations of the species involved, represented by the variables A, B, C, and D, as indicated. Please note that the equilibrium expression is based on molar concentrations since we are using brackets to represent these concentrations.
The equilibrium expression can be written as follows:
[H3O+] * [CHO−2]
--------------------
[HCHO2] * [H2O]
So, the equilibrium expression for the given chemical equation is:
[C] * [D]
----------------
[A] * [B]
Now, you can substitute the given variables with the corresponding concentration values to calculate the equilibrium constant (K).
So the equation transformed to the letters is
A(aq) + B(l) ==> C(aq) + D(aq)
The whole point of this problem is that when writing equilibrium constants one does NOT include pure liquids or solids so
Keq for this one is (C)(D)/(A)