More errors are made on mechanistic questions through a lack of understanding of pH than any other topic. This idea is introduced in high school and first year college chemistry classes, yet it becomes obvious at the second year level how little students actually understand about what species will, and will not, be present in a reaction flask at a certain pH level. This doesn’t need to be complicated, and we won’t be doing any calculations, but knowing what is present in base versus acid, and how it affects mechanism, will clear up a lot of confusion.

For “neutral” read inert or unreactive as there are no strong acids or bases present. We can change that by introducing an acid or a base and making the system more reactive by changing the pH. This will often be a catalytic process since the added species, acid or base, speeds up reaction but is then regenerated in the last step of the mechanism.