Acidic compounds give foods a tart or sour taste. Aqueous solutions of acids are electrolytes and conduct electricity. Many metals react with aqueous solutions of acids to produce hydrogen ions, H+. Bases have a bitter taste or a slippery feel. It also can conduct electricity because it is an electrolyte as well. Bases produce hydroxide ions, OH-. Acids are classified as strong or weak depending on the degree to which they dissociate in water. Strong acids are completely ionized in aqueous solution. Weak acids are partially ionized in aqueous solution. It is the same with bases. The pH scale is used to measure the molarity of hydrogen ions in a solution. Acids and bases can also be identified by using indicators. Acids turn phenol red to yellow and bases turn phenolphthalein pinkish red.



  1. Label six test tubes and a beaker.
  2. Place 3 drops of phenolphthalein in test tubes #2 and 4.
  3. Place 2 drops of NaOH in test tube #6 and the beaker.
  4. Place 3 drops of HCl in test tube #5.
  5. Fill the beaker with 50mL of water.
  6. Quarter-way fill test tubes #1, 2, 3, and 4 from the beaker.
  7. Pour all contents from test tubes #1, 2, 3, 4 back to the beaker.
  8. Fill test tubes #1, 2, 3, 4, and 5 from the beaker.
  9. Pour all contents from test tubes #1, 2, 3, 4, and 5 back to the beaker.
  10. Fill all six test tubes.


1. What happened in step #6, why? ???
2. What happened in step #7, why? ???
3. What happened in step #8, why? ???
4. What happened in step #9, why? ???
5. What happened in step #10, why? ???
6. What is the neutralization equation? ???
*Honors Extension
7. If the hydroxide-ion concentration of an aqueous solution is 1 10-3 M, what is the [H+] in the solution? Is the solution acid, basic, or neutral?

How to do this assignment?

Chemistry in March