pH of a weak acid (and the two assumptions) | A-level Chemistry worked exam question

How to calculate the pH of a weak acid from Ka, using butanoic acid, and how to state the two assumptions so you get both marks. A 5-mark question. Pause the video and try it yourself first, then follow along. Suits AQA and Edexcel A-level Chemistry. Every question is original. 0:00 Intro 0:13 The question 0:49 Key idea 1:04 Part (a): the Ka expression 1:23 Part (b): the pH 1:53 Part (c): the two assumptions 2:21 Recap and common mistakes Independent resource. Not affiliated with or endorsed by AQA or Pearson Edexcel. #alevelchemistry #chemistry #revision