Question

Acetic acid has a Ka of 1.75x10^-5. The weak acid approximation (for this class) would be allowed for which of the following initial concentrations of acetic acid?

a. 1.75E^-6
b. 1.75E^-5
c. 0.00175
d. 0.0175
e. 0.175

Answer 1

e. 0.175

Step-by-step explanation:

The equilibrium constant of a reaction is the value of its reaction quotient when at equilibrium. The equilibrium concentration of a product or reactant depends on the initial concentrations and equilibrium constant of the reactants and products.

The weak acid approximation depends on the initial concentration and equilibrium constant (
`K_a`). The farther the initial concentration and equilibrium constant are from one another, the more likely the approximation would be valid.