Name ________________________________ Period ____________
Chemistry I Date _____________
Purpose: Use various indicators to classify solutions as acids, bases, or neutral.
1. Use a well plate. Be sure to clean it thoroughly before beginning lab.
2. Add ten drops of acetic acid solution to three horizontal wells.
3. Test the first well with a strip of red litmus paper and then blue litmus paper using tweezers. Record results in the table.
4. To the first well, add one drop of phenolphthalein. Record results in the table.
5. To the second well, add one drop of bromothymol blue. Record results in the table.
6. To the third well, add one drop of methyl-orange. Record results in the table.
7. Repeat steps 2-7 with each of the samples. Make sure you do not confuse the samples.
1. What is an indicator? Name three examples used in this lab.
2. What is an electrolyte? What three substances are usually electrolytes?
3. Predict whether water is acidic, basic or neutral. Why?
Solution Formula Red litmus Blue litmus Phenoph-
Methyl orange A-B-N
Acetic acid HC2H3O2
Isopropyl alcohol C3H7OH
Magnesium sulfate MgSO4
Salt water NaCl
Baking Soda NaHCO3
Indicators Acid Base Neutral
Red litmus paper Red Blue Red
Blue litmus paper Red blue Blue
Phenolphthalein Clear Bright pink Clear
Methyl orange Red orange NA
Bromothymol blue Yellow Blue Green