Buffer Solutions adding acid or base

[beccaram002]

Homework Statement

A buffer is prepared by dissolving 1.00 mole HLac (with a ka=8.0x10-3) and 1.00 mole of sodium lactate (NaLac) in enough water to form one (1) liter of solution. Calculate the [H+] and the pH of the buffer.
36 minutes ago - 3 days left to answer.
Additional Details
12 minutes ago

There is another part to this and it says
Using the information from that problem: supposed we add a strong acid or base to the buffer; calculate the following:
a. [HLac], [Lac], [H+] and the pH after adding 1L of 0.15 M-HCl
b. [HLac], [Lac], [H+], and the pH after adding 1L of 0.15M-NaOH

Homework Equations

pH=pka-log[HA]/[A-]

The Attempt at a Solution

I know the answer to the first part is found to be pH=2.1 I just have no idea how to find the part a and b for the second half.

 

[opuktun]

you can always try writing the equilibrium equation then solve for them using the first principles:

A + B <-> C
1 1 0
1-x 1-x x
K = x/(1-x)^2 etc