✔ 最佳答案
In volumetric analysis, the molar concentration measurement of various chemical has to be accurate. Tap water contains many impurities that you don't want in your analysis. Depending on where you live, these impurities include chlorine, trihalomethanes, haloacetic acids, Arsenic, perchlorate, and lead, just to name a few. Distilled water, on the other hand, contains pure H2O. Using it will make your analysis more accurate.
2009-03-12 01:07:24 補充：
Hi mariafransisca_lim,
Sorry that I missed your follow-up question. Those impurities will remain in your flask and likely increase the molar concentration of your analysis. In science, we must always try to keep the number of variables under control to maintain objectivity in our experiment.
