A weak acid, HA, has an ionization constant of 9.29 x 10-6. If we prepare a solution that is 0.727 M in HA what percent of the acid will be ionized?
HA>>H + A
do the ice
(Moles-x) x x
9.29E-6= x^2/(.727-x)
now multiply this out, it is a quadratic, use the quadratic equation. Solve for x
percent ionized= x/.727 * 100
To find the percent of the acid that will be ionized, we need to calculate the degree of ionization using the ionization constant (Ka) of the weak acid.
The ionization constant, Ka, is defined as the ratio of the concentration of the products (H+ and A-) to the concentration of the reactants (HA).
The equation for the ionization of the weak acid HA is as follows:
HA ⇌ H+ + A-
Given:
Ka = 9.29 x 10^-6
Concentration of the weak acid HA = 0.727 M
Let's denote the degree of ionization as x.
The concentration of H+ and A- can be approximated as x M.
The concentration of undissociated weak acid HA can be approximated as (0.727 - x) M.
Since Ka is a small value, we can assume that the degree of ionization (x) will be very small compared to the initial concentration, 0.727 M.
We can set up the equation for Ka to calculate the value of x:
Ka = [H+][A-] / [HA]
9.29 x 10^-6 = x * x / (0.727 - x)
By solving this quadratic equation, we can find the value of x, which represents the degree of ionization.
Once we obtain the value of x, we can calculate the percent of the acid ionized by dividing x by the initial concentration of the weak acid (0.727 M) and multiplying by 100.
This method allows us to determine the percent of the acid that will be ionized based on the given ionization constant and the initial concentration of the weak acid.