What happens if a student adds distilled water to a flask before starting the titration?

Answer 1

It does not affect the titration as long as the distilled water is not contaminated. You may be thinking (or your instructor may be asking) why adding distilled water doesn't dilute the material you are titrating. The answer is that it does BUT it also dilutes the titrant. This is not a very good answer but it is understood by most students; I prefer to say that the distilled water adds no moles of the titrant OR the material being titrated; therefore, there is no effect.