Final answer:
To distinguish between an acid solution and tap water, use pH paper to observe a color change indicating low pH for the acid, or add a pH indicator like phenolphthalein to see if there's any color change.
Step-by-step explanation:
To distinguish the acid solution from tap water, an experimenter can perform a simple test using pH paper or a pH meter. When pH paper is dipped into each beaker, the paper will change color based on the pH of the solution. The paper dipped into the 1.0 M HCl will indicate a low pH (around pH 1), which is highly acidic, whereas the paper dipped into the tap water should show a neutral pH of around 7. Another method is to add a few drops of a pH indicator, like phenolphthalein, to each beaker. The acid solution will remain clear, while the tap water might turn pink if it is slightly basic or remain clear if neutral. These methods are based on the property that acids have lower pH values compared to neutral substances like pure water.