[karadda]

Hello!

this was a lab where we start with an unknown monoprotic weak acid "HA" (1.01 M) and measure its pH: 3.28
from this i calculated the concentration of the hydronium ion to be: .000525 M

so i have:

HA + H₂O H₃O⁺ + A^-
initial concentration of HA is 1.01 M
equilibrium concentration of hydronium ion is .000525 M
equilibrium concentration of A^- is .000525 M
equilibrium concentration of HA is 1.00948 M


To this solution i added 20 mL of a base "NaA" (1.0 M)
the pH of this solution was recorded as: 1.98

here is where i'm getting stuck:
I need to determine the concentration of HA and A- after mixing, and the equilibrium concentrations of HA, A^- and H₃O⁺.

[rabolisk]

Your pH went down after adding a base to an acidic solution?

[karadda]

yes, this confused me too. But im just going to work with the numbers i recorded.