Parts of this sub-topic could be a real problem if you are a Standard Level student - somehow there seems to be a mismatch between the content in the core topics and the content of the core part of the option. In Topic 8: Acids and bases, which forms part of the main core, you do cover the definition of pH, but you do not cover acid or base ionization constants, Ka or Kb, or pKa or pKb, or the relationship between pKa...