Please help.
Calculate the pH at the following points during the titration of 100.0 mL of 0.20 M acetic acid (Ka for acetic acid = 1.8 x 10-5) with 0.10M sodium hydroxide
1. before addition of any base
2. after addition of 30.0mL of base
3. after addition of 100.0mL of base
4. after addition of 200.0mL of base
5. after addition of 250.0 mL of base