What happens if a student adds distilled water to a flask before starting the titration?
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.
If a student adds distilled water to a flask before starting a titration, it can dilute the concentration of the analyte or the substance being titrated. This can affect the accuracy and precision of the titration results.
During a titration, a known volume of a solution with a known concentration, known as the titrant, is slowly added to a solution of the analyte until the reaction between the titrant and analyte is complete. The point at which the reaction is complete is called the equivalence point, and it is usually detected using an indicator or an instrument.
By adding distilled water to the flask before the start of the titration, the total volume of the solution increases. As a result, the concentration of the analyte decreases because the amount of analyte is still the same, but it is now dissolved in a larger volume of solution. This dilution affects the stoichiometry of the reaction between the analyte and the titrant, leading to inaccurate results.
To avoid dilution errors, it is important to make sure that the solution being titrated is not diluted with any additional substances before the titration. It is necessary to accurately measure and prepare the solution to be titrated, ensuring its concentration remains constant throughout the titration process.