Lab: Properties of Acids and Bases
Background
Acids ionize in aqueous solutions to produce hydronium ions (H3O+). The strength of an acid
depends on the degree to which it ionizes. Strong Acids ionize almost completely, while weak acids ionize
to a lesser degree. Bases create hydroxide ions (OH-) in aqueous solution. Arrhenius bases (like NaOH) do
this by dissociating in aqueous solution to produce hydroxide ions. A Bronsted-Lowry bases (like NH3) can
do this by accepting a proton (H+) from water to produce hydroxide ions.
This lab will help provide an understanding of the properties and reactions of acids and bases that
result from the presence of free H3O+ or OH- in solution. The lab will involve interactions of acids and
bases with indicators, a neutralization reaction, single and double replacement reactions, a reaction with a
carbonate, and reactions with metals.
Objectives
•
•
•
•
•
Observe the effects of acids and a base on various indicators.
Observe reactions of acids and metals.
Observe a reaction of an acid with a carbonate.
Observe a neutralization reaction.
Observe the effects of some common household substances on various indicators.
Materials
2 small test tubes
1 large test tube
2 piece red litmus
2 piece blue litmus
Stir rod
Well plate
1 roll pH paper
Phenolphthalein
Wood splint
Matches
6 M HCl
6 M HC2H3O2
1 M HCl
Gas collection apparatus
0.5 M NaOH Lemon Juice Detergent
Bleach
Coffee
Soda
Procedure
Part A: Reactions of Acids with Metals
1. To separate depressions on one side of your well plate, add small quantities of each of the following:
zinc, magnesium, iron, and copper.
2. To each depression, add just enough 6 M HCl to cover the metal. Observe the relative reactivities of the
metals with this acid. Record your observations in the data table provided.
3. On the other side of your well plate, repeat steps 1 and 2 using 6 M HC2H3O2 in place of the HCl.
Contrast each metal’s reactivity with HC2H3O2 against the metals reactivity with HCl. Discard the
contents of the well plate (large metal pieces in the trash, small down the drain) and rinse and dry the
spot plate. Record your observations in the data table provided.
4. Next you will attempt to verify the identity the gas that was being produced in the previous reactions of
metals and acids. To do this, place a small quantity of zinc in one of the smaller test tubes. Add enough
6 M HCl to cover the zinc. As the reaction proceeds, hold an inverted small test tube over the reaction
for about 1 minute. Without turning the test tube upright, quickly insert a burning wood splint into the
test tube. Repeat entire process as desired. When finished, discard the contents of the well plate and
clean and dry the plate.
Part B: Reactions of Acids with Carbonates
1. Half fill a small test tube with limewater solution. Place a small amount of CaCO3 into a second clean,
large test tube. Add enough 6 M HCl to just cover the carbonate. Immediately insert the rubber stopperglass tubing apparatus into the large test tube containing the CaCO3 and HCl.
2. Submerge the open end of the tubing into the limewater (aqueous calcium hydroxide) solution in the
smaller test tube. Observe and look for a white precipitate. A white precipitate formed from the
reaction of a gas and limewater solution indicates the identity of the gas as CO2.
3. Discard the solutions and clean and rinse the test tubes.
Part C: Effect of Acids and Bases on Indicators
1. To separate depressions in your well plate, add about five drops of each of the following:
6 M HCl;
6 M HC2H3O2; and 0.5 M NaOH.
2. Retrieve one clean, dry piece of red litmus paper and place upon a paper towel on the lab table. Using a
clean stir rod, dip one end in the depression containing 6 M HCl. Touch the wet end of the stir rod to the
red litmus paper to create a small dot of 6 M HCl upon the dry litmus paper. Wash the stir rod and
repeat with the other two solutions, using the same piece of litmus paper to test all three solutions.
3. Next, repeat step 2, this time with blue litmus paper.
4. Next, repeat step 2, this time with pH paper.
5. Finally, add one drop of phenolphthalein to the solution in each depression. Discard the solutions and
rinse the well plate with water. Dry well plate with a paper towel.
Part D: Acidity and Basicity of Household Substances
1. To different depressions in your well plate, add about 5 drops of each of the following: lemon juice,
coffee, bleach, detergent, and soda.
2. Test each substance as you did in Part C, using 1 piece of red litmus, 1 piece of blue, 1 piece of pH
paper, and phenolphthalein.
Part E: Neutralization Reactions
1. Add about 10 drops 1.0 M HCl to a clean test tube. Add 1 drop of phenolphthalein. Test with pH paper.
2. Add 0.5 M NaOH drop by drop to the acid in the test tube. After the addition of each drop, swirl the test
tube gently so the drop mixes thoroughly with the acid. Count the total number of drops of NaOH
needed to cause a permanent color change. Once a color change is observed, test the mixture with pH
paper by dipping your cleaned stir rod in it and placing a small dab on the pH paper then referencing the
color of the wetted paper with the color chart.
Data and Data Analysis
Part A
1. What type of reaction occurs between a metal and an acid? ___________________________________
2. Write balanced chemical equations for the reaction of each metal with HCl (include phases):
a. Zinc
_______________________________________________________________
b. Magnesium
_______________________________________________________________
c. Iron
_______________________________________________________________
d. Copper
_______________________________________________________________
3. Write balanced chemical equations for the reaction of each metal with HC2H3O2 (include phases):
a. Zinc
_______________________________________________________________
b. Magnesium
_______________________________________________________________
c. Iron
_______________________________________________________________
d. Copper
_______________________________________________________________
4. Place the metals in order of overall reactivity:
_________________ __________________ __________________
__________________
most reactive --------------------------------------------------------------------------> least reactive
5. Compare reactivates of metals (very fast, fast, slow, very slow, no apparent rxn):
with 6 M HCl
with 6 M HC2H3O2
Zinc
Magnesium
Copper
Iron
6. Compare the reactivity of zinc and 6 M HCl to zinc and 6 M HC2H3O2. Look up the terms strong acid
and weak acid in your text and learn their definitions.
a. Even though both acids are of the same concentration, explain why 6 M HCl was more reactive.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
7. What were the results of the burning splint test?
a. What happened? _______________________________________________________________
_________________________________________________________________________________
b. Why did it happen? _____________________________________________________________
_________________________________________________________________________________
c. Write a balanced chemical equation (including phases) for the reaction that caused the explosion.
_________________________________________________________________________________
Part B
8. What were the results of the limewater test?
a. What happened? _______________________________________________________________
_________________________________________________________________________________
b. Why did it happen? _____________________________________________________________
_________________________________________________________________________________
c. Write a balanced chemical equation (including phases) for the reaction that created the CO2.
_________________________________________________________________________________
d. Write a balanced chemical equation (including phases) for the reaction between CO2 and
limewater that created the precipitate.
_________________________________________________________________________________
Part C
red litmus
blue litmus
pH paper
phenolphthalein
(red or blue?)
(red or blue?)
(what color?)
(pink or colorless)
6 M HCl
6 M HC2H3O2
0.5 M NaOH
9. Red litmus indicates that a substance is a(n) __________________ when it turns __________________.
10. Blue litmus indicates that a substance is a(n) __________________ when it turns _________________.
11. Phenolphthalein indicates that a substance is a(n) ________________ when it turns ________________.
Part D
red
litmus
blue
litmus
(red or blue?)
(red or blue?)
pH paper
(what color?)
phenolphthalein
(pink or
colorless)
acid or base?
√ Check the most acidic
solution
√√ Double-check the
most basic solution
bleach
soda pop
detergent
coffee
lemon juice
Part E
12. How many drops of 0.5 M NaOH were required to neutralize 10 drops of 1.0 M HCl? ______________
13. Explain why it required this many drops. In other words, why didn’t it require only 10 drops of NaOH?
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________