How do can you find the difference between these acids/bases with only one indicator?
We have 0.1M NaOH, H2SO4, HCl, AlCl3, and Na2CO3. We know the pH of all the solutions (AlCl3 = 2.9, H2SO4 = 0.7, HCl = 1, Na2CO3 = 11.8, NaOH = 13). We only can use 1 indicator to determine what acid/base is which in unmarked bottles. We were thinking of using indigo carmine (11.4-13.0 pH range) to determine what was NaOH and Na2CO3, but then we wouldn't have an indicator if we wanted to do titrations with the NaOH later (we were thinking of doing strong base/strong acid titrations later). Any ideas how to determine these acids/bases apart with only 1 indicator?
Use a universal indicator. Look that up on Google.
To differentiate between the acids and bases in the given solutions using only one indicator, you can choose an indicator that undergoes distinct color changes in different pH ranges specific to each acid or base. One possible indicator that can be employed in this case is bromothymol blue.
Bromothymol blue has a pH range of 6.0 to 7.6, and it changes color based on the acidic or basic nature of the solution. Here's how you can use it to identify the acids and bases:
1. Start with the one indicator you have, which is bromothymol blue. Prepare a small amount of each solution in separate containers.
2. Begin by adding a few drops of bromothymol blue to the first solution, H2SO4 (pH = 0.7). Note the color change, if any. The bromothymol blue should turn yellow in the presence of the acidic solution.
3. Repeat the process with the second solution, HCl (pH = 1). Again, note the color change. The bromothymol blue should also turn yellow in this case.
4. Now move on to the third solution, AlCl3 (pH = unknown). Add a few drops of bromothymol blue and observe any color change. If the bromothymol blue does not change color or remains blue or green, it indicates that the solution is neither strongly acidic nor basic.
5. Proceed to the fourth solution, Na2CO3 (pH = 11.8). When you add bromothymol blue to this solution, it should turn blue or green, indicating the presence of a weak base.
6. Finally, test the fifth solution, NaOH (pH = 13). The bromothymol blue should turn a deep blue color, signifying the presence of a strong base.
By using bromothymol blue as the indicator, you can differentiate between the acids (H2SO4 and HCl), the neutral solution (AlCl3), and the bases (Na2CO3 and NaOH) based on the distinct color changes observed. Keep in mind that this method relies on the specific pH range of bromothymol blue, so other indicators with different pH ranges may need to be used to identify solutions falling outside this range.