pH and Determining pH of Solutions
Purpose: The purpose of this lab investigation is to develop an understanding of pH, the pH scale, and how the pH of acid or base solutions are measured.
Materials and Methods: This investigation requires pH paper (1 to 14), and dropper bottles of orange juice, milk, coffee, coke, stomach acid (0.1M HCl), 0.1M NaOH, and vinegar.
Experiment: Tear off about an inch of pH paper and add one drop of a solution to it. Observe a color change on the paper and compare it to the pH chart on the dispenser. Do this for each solution.
Record the pH of each solution below:
| orange juice | |
| milk | |
| coffee | |
| coke | |
| stomach acid | |
| 0.1M NaOH | |
| vinegar |
Conclusion:
Distinguish between acids and bases.
How does an HCl solution of pH 3 compare to one that has a pH of 6?
What is the significance if something is determined to have a pH of 7?