A weak acid solution has a pH of 3.86. if the acid solution has a concentration of 0.38, what would the Ka be for this acid
To determine the Ka for the weak acid, we first need to convert the pH to the concentration of the hydronium ion ([H3O+]) in the solution.
The pH is given as 3.86, which means that the hydronium ion concentration ([H3O+]) is 10^-pH.
[H3O+] = 10^-3.86
[H3O+] = 1.39 x 10^-4
Now, we can use the concentration of the weak acid (0.38 M) and the hydronium ion concentration to determine the Ka.
Ka = [H3O+][A-] / [HA]
Since we know that the concentration of the weak acid ([HA]) is 0.38 M, and the concentration of the hydronium ion ([H3O+]) is 1.39 x 10^-4 M, we can substitute these values into the equation:
Ka = (1.39 x 10^-4)(0.38) / 0.38
Simplifying the equation, we find:
Ka = 1.39 x 10^-4
Therefore, the Ka for this weak acid is 1.39 x 10^-4.