Case Your pharmaceutical analysis company has been contacted by an important client and asked to analyse a batch of phosphate solutions for use in enemas. The description of your brief states that you are supposed to analyse the APIs in this solution following standard quality assurance guidelines.
Typical analysis methods used for quality purposes are based on titration reactions. A certain amount of solution is diluted with water. A known amount of this solution is then titrated with sodium hydroxide or hydrochloric acid depending on the API. Phenolphthalein and methyl red solutions are typically used as indicators.

a.) Formulate the relevant chemical equations.