Repeat Experiment 1 using phenolphthalein as the indicator instead of bromothymol blue. Record the color of each solution after the addition of phenolphthalein. It may be helpful to turn on the Color Blind Function in the lab to determine the color of each solution.

\begin{tabular}{|c|c|c|}
\hline Test Tube Number & Solution & Color After Addition of Phenolphthalein \\
\hline 1 & water & \\
\hline 2 & acetone & \\
\hline 3 & 5 M citric acid & \\
\hline 4 & [tex]$5\%$[/tex] vinegar & \\
\hline 5 & 4 M ammonia & \\
\hline 6 & diluted bleach & \\
\hline
\end{tabular}



Answer :

Sure, I can guide you through the expected results after adding phenolphthalein to each of the solutions in the test tubes. Here's a step-by-step solution for what you'll observe:

1. Test Tube 1: Water
- Water is a neutral solution, meaning its pH is close to 7. Phenolphthalein remains colorless in neutral solutions.
- Color Observation: Colorless

2. Test Tube 2: Acetone
- Acetone is a neutral substance, and like water, it does not cause phenolphthalein to change color.
- Color Observation: Colorless

3. Test Tube 3: 5 M Citric Acid
- Citric acid is a strong acid solution which means it has a low pH. Phenolphthalein remains colorless in acidic solutions.
- Color Observation: Colorless

4. Test Tube 4: 5% Vinegar
- Vinegar, which contains acetic acid, is also an acidic solution thus it has a low pH. Phenolphthalein will remain colorless in such acidic environments.
- Color Observation: Colorless

5. Test Tube 5: 4 M Ammonia
- Ammonia is a basic solution with a high pH. Phenolphthalein changes to pink in basic solutions.
- Color Observation: Pink

6. Test Tube 6: Diluted Bleach
- Diluted bleach is another basic solution. Therefore, phenolphthalein will change to pink in this solution as well.
- Color Observation: Pink

So, summarizing these observations in the provided table:

```
\begin{tabular}{|c|c|c|}
\hline Test Tube Number & Solution & Color After Addition of Phenolphthalein \\
\hline 1 & water & Colorless \\
\hline 2 & acetone & Colorless \\
\hline 3 & 5 M citric acid & Colorless \\
\hline 4 & [tex]$5 \%$[/tex] vinegar & Colorless \\
\hline 5 & 4 M ammonia & Pink \\
\hline 6 & diluted bleach & Pink \\
\hline
\end{tabular}
```

These changes are due to the pH-dependent nature of phenolphthalein, which remains colorless in acidic and neutral solutions but turns pink in basic solutions.

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