What is the pH when 200 mL 0.1 M NaOH is mixed with 300 mL water? I am stuck here. I know V1C1 = V2C2 but I need help at this point. I don't know how NaOH reacts with water, and how this would affect the pH of the final solution. I also don't know whether or not I should use the Henderson-Hasselbalch equation. Thank you in advance for your help!