CHEM 2115 Lab Report
Name
Experiment #10
Section #
Acids, Bases, Salts & Buffers
Station #
Chem I Lab
Date
A. Acid-Base Neutralization
I. Describe your observations in the table below.
Observations
Solid residue
AgNO3 addition
Flame test
II. Write a balanced chemical equation for the neutralization reaction you observed.
B. pH Measurement
I. Record the measured pH for the substances listed below.
Substance
Lemon Juice
Orange juice
Milk
pH
Substance
Ammonia
Laundry
detergent
Dishwashing
detergent
pH
Substance
Baking soda
Aspirin
Buffered
aspirin
pH
C. Acid-Base Indicators
Indicator
Color in 0.05 M HCl
Color in 0.05 M NaOH
Methyl red
Bromcresol green
Phenolphthalein
Methyl orange
Methyl violet
I. Which indicator would be best in distinguishing between 0.05 M HCl and 0.05 M NaOH?
Which would be the worst? Justify your answer.
D. Behavior of Salt Solutions
Salt
Solution pH
Sodium acetate
Sodium carbonate
Ammonium chloride
Sodium chloride
Boiled distilled water
I. Which ions exhibit significant Brønsted acid character? Brønsted base character? Are your
results consistent the expected results based on the theory of hydrolysis?
E. Buffers
Buffer
Initial pH
pH after adding HCl
pH after adding NaOH
Solution A
Solution B
Solution C
Solution D
Boiled water
I. Which solutions are able to buffer well against acid? Against base? Explain.
II. Are any solutions able to buffer well against both acid and base? Explain.
III. Do any solutions show little or no buffering ability? Explain.
IV. Write equations to show how a buffer made up of equimolar amounts of acetic acid,
CH3COOH, and acetate, CH3COO-, would behave when (a) HCl is added and (b) NaOH is
added.
V. At what point is a buffer solution no longer effective in resisting a pH change when a strong
acid is added?