OXIDATION AND REDUCTION REACTIONS
EXPERIMENT 24
PURPOSE
To investigate and compare the relative ease of oxidation and reduction of copper, lead, and zinc.
DEFINITIONS
Reduction, oxidation, single replacement reaction, net ionic reaction, activity series.
BACKGROUND
The rusting of iron and the combustion of gasoline are common examples of oxidation–reduction
reactions, often abbreviated redox reactions. Oxidation reactions are also thought to be partly responsible
for the aging of the human body. Every oxidation reaction involves a transfer of electrons from the
substance oxidized to the substance reduced. A substance undergoing oxidation gives up, or loses,
electrons; a substance undergoing reduction gains electrons. The ease with which a substance oxidizes
depends on the substance. For instance, iron oxidizes more easily than either silver or gold.
For example, when aluminum is added to a solution of silver nitrate, a single replacement reaction takes
place because aluminum is more active than silver, as shown on Regents table J. The reaction can be
represented by:
Al(s) + 3AgNO3(aq)  3Ag(s) + Al(NO3)3(aq)
Since this reaction takes place in water and since AgNO3 and Al(NO3)3 are both water soluble, the net
ionic reaction is:
Al(s) + 3Ag+(aq)  3Ag(s) + Al+3(aq)
It is easy to see that Al is oxidized (it is more active) and silver ion is reduced (it is less active). The halfreactions are:
Al  Al+3 + 3e- (oxidation)
Ag+ + e-  Ag
(reduction)
In this experiment, you will study some oxidation–reduction reactions that occur between metals and
metal ions. On the basis of your experiments, you will organize these substances into a series according to
their relative ease of oxidation.
MATERIALS
spot plate
zinc powder
copper pieces
lead pieces
0.1 M copper(II) nitrate
0.1 M lead(II) nitrate
0.1M zinc nitrate
SAFETY


Wear safety goggles.
Copper and lead compounds are toxic. Wash your hands at the end of the lab.
OXIDATION AND REDUCTION REACTIONS
EXPERIMENT 24
PROCEDURE
As you perform the experiment, record your observations in Data Table 1.
1. Place each combination of metal and metal ion into the wells of the spot plate as laid out in Data
Table 1. Use only one piece of copper, one piece of lead, and a few granules of zinc powder for the
metal samples. Use only three drops of each metal ion solution. Do not contaminate the solutions by
mixing droppers.
2. Allow the spot plate to stand undisturbed for 10 minutes.
3. Record your observations in Data Table 1, briefly describing evidence of any reaction. If no reaction
is visible, write NR.
4. To clean up, throw the metal pieces in the marked container on the back bench, and rinse the
solutions on the spot plate in the sink with plenty of water. Clean the spot plates and return to the
back bench.
ANALYSIS
1.
2.
3.
4.
5.
6.
State the most important safety concern in this lab and the required precaution you took.
Write balanced net ionic equations for any reactions that you observed.
Which metal was oxidized by both of the other two metal ions?
Which metal was not oxidized by either of the other metal ions?
List the metals in order of most easily oxidized first. Compare this order to that in Regents Table J.
Write balanced half reactions for the reduction of the halogens, F2, Cl2, Br2, and I2. List these in the
order of most easily reduced first (you will need to refer to Regents Table J).
7. Many metals are oxidized by aqueous solutions of acids (such as HCl) to produce hydrogen gas and
metal ions. Based on the results of this lab, which of the three metals studied in this lab would be
most easily oxidized by HCl? Write a balanced equation.
8. Honors: What was the most probable source of error that would lead to incorrect observations?
OBSERVATIONS
Data Table 1. Observations of Reactions
Cu+2
Cu(s)
Pb(s)
Zn(s)
Pb+2
Zn+2