A 9.00 M solution of a weak acid, HA, has a pH of 1.30

1.) calculate [A-] at equilibrium

2.) calculate [HA] at equilibrium

Use pH to get (H^+).
Ka = (H^+)(A^-)/(HA)
(A^-) = (H^+).
(HA) = 9
Plug and chug.
Post your work if you get stuck.

To calculate the concentration of the conjugate base, A-, at equilibrium, we need to first calculate the concentration of the hydrogen ions, H+, in the solution.

Since we are given the pH of 1.30, we can convert this value to the concentration of H+ using the equation:

[H+] = 10^(-pH)

Therefore, [H+] = 10^(-1.30) = 0.0501 M

Since the concentration of the conjugate base, A-, is equal to the concentration of the hydrogen ions, [A-] = [H+], we can conclude that [A-] = 0.0501 M.

Next, we need to calculate the concentration of the weak acid, HA, at equilibrium.

We are given that the concentration of the solution is 9.00 M, so the concentration of HA at equilibrium is also 9.00 M.

Therefore, [HA] = 9.00 M.

Now, let's recap the results:

1.) [A-] at equilibrium = 0.0501 M
2.) [HA] at equilibrium = 9.00 M