. Calculate the Ka for a 0.33M weak acid solution that has a pH equal to 4.22.1.1 x 10-82.3 x 10-53.02 x 10-71.80 x 10-4

To calculate the Ka for a weak acid solution, we need to use the formula for Ka and the definition of pH. Here are the steps:

1. The pH is given as 4.22. The pH is the negative logarithm of the concentration of H+ ions. So, we can find the concentration of H+ ions by taking the inverse log of the pH.

   [H+] = 10^-pH = 10^-4.22 = 6.02 x 10^-5 M

2. The Ka expression for a weak acid HA dissociating into H+ and A- is Ka = [H+][A-]/[HA]. In a weak acid solution, the concentration of H+ ions is equal to the concentration of A- ions. So, we can simplify the expression to Ka = [H+]^2/[HA].

3. Substitute the values into the Ka expression:

   Ka = (6.02 x 10^-5)^2 / 0.33 = 1.09 x 10^-9

So, the Ka for the weak acid solution is approximately 1.09 x 10^-9.