Understanding CuSO4/Al Foil Reactivity with NaCl - Al in CuSO4

  • Thread starter lightarrow
  • Start date
In summary, the reason why an aqueous solution of CuSO4 does not react with aluminum foil is due to the thin protective coating of Al2O3 on the aluminum metal preventing the reaction from occurring. However, by adding NaCl to the solution, it becomes ionically equivalent to CuCl2 which acts as an acid and readily reacts with aluminum. To investigate the reaction without NaCl, sanding the Al foil to remove the oxide coating or using a more concentrated CuSO4 solution can help initiate the reaction. Additionally, the difference between an aqueous solution of CuCl2 and separate Cu++ and Cl- ions is that the Cu++ may partially oxidize Cl- to Cl2, which reacts more easily with the Al foil
  • #1
lightarrow
1,965
61
Why an acqueous solution of CuSO4 doesn't react with an aluminum foil, but, if we add a little amount of NaCl, the reaction starts immediately?
 
Chemistry news on Phys.org
  • #2
Aluminum should react with an aqueous solution of since it is a more reactive metal, it should displace Copper ions out of solution.
However, the rate of this reaction might be very slow and possible the thin protective coating of Al2O3 on the Aluminum metal prevents the reaction from occurring.

However, by adding NaCl to a solution of CuSO4, you are forming a solution which is ionically equivalent to CuCl2. A Copper (II) Chloride solution acts as an acid and will react with Aluminum metal quite readily.
 
  • #3
If you want to investigate the reaction without the NaCl, I would recommend sanding the Al foil to remove the oxide coating. Also, you can try to gently heat the reactants until you start to see something happening. You can try using more a concentrated CuSO4 solution as well.
 
  • #4
mrjeffy321 said:
Aluminum should react with an aqueous solution of since it is a more reactive metal, it should displace Copper ions out of solution.
However, the rate of this reaction might be very slow and possible the thin protective coating of Al2O3 on the Aluminum metal prevents the reaction from occurring.

However, by adding NaCl to a solution of CuSO4, you are forming a solution which is ionically equivalent to CuCl2. A Copper (II) Chloride solution acts as an acid and will react with Aluminum metal quite readily.
What makes an acqueous solution of CuCl2 different from a solution of Cu++ and Cl- separately? Do you mean that, maybe, Cu++ partially oxidizes Cl- to Cl2 which reacts more easily with Al (covered with its oxide)?
 
  • #5
dtx said:
If you want to investigate the reaction without the NaCl, I would recommend sanding the Al foil to remove the oxide coating. Also, you can try to gently heat the reactants until you start to see something happening. You can try using more a concentrated CuSO4 solution as well.
I already know that Al without the oxide layer reacts immediately even with water itself, forming again the oxide layer.
 
Last edited:

1. What is the purpose of the experiment involving CuSO4/Al foil reactivity with NaCl - Al in CuSO4?

The purpose of this experiment is to investigate the reactivity between copper sulfate (CuSO4) and aluminum (Al) when exposed to sodium chloride (NaCl) in the presence of Al in CuSO4. This reaction is also known as a displacement reaction, where the more reactive metal (Al) replaces the less reactive metal (Cu) in a compound (CuSO4).

2. What are the materials needed for this experiment?

The materials needed for this experiment include CuSO4 solution, aluminum foil, sodium chloride solution, a beaker or test tube, and a stirring rod. Safety equipment such as goggles and gloves should also be used.

3. How does the reaction between CuSO4 and Al in the presence of NaCl occur?

The reaction occurs through a series of redox reactions. The aluminum metal is oxidized, losing electrons to form aluminum ions (Al3+). These electrons are then transferred to the copper ions (Cu2+), reducing them to copper metal. Meanwhile, the chloride ions (Cl-) in the NaCl solution act as a spectator ion and do not participate in the reaction.

4. What is the expected outcome of this experiment?

The expected outcome of this experiment is the formation of copper metal and the release of aluminum ions into the solution. The solution will also turn blue due to the presence of excess copper ions. The aluminum foil used in the experiment will also appear thinner and may have holes due to the loss of aluminum atoms.

5. What are the possible sources of error in this experiment?

Possible sources of error in this experiment include incorrect measurements of the materials used, impurities in the CuSO4 or NaCl solutions, and incomplete reactions due to inadequate stirring or insufficient contact between the reactants. Other factors such as temperature and pressure can also affect the rate of the reaction and should be kept constant for accurate results.

Similar threads

Replies
9
Views
1K
Replies
21
Views
3K
  • Biology and Chemistry Homework Help
Replies
3
Views
3K
  • Chemistry
Replies
1
Views
1K
  • Biology and Chemistry Homework Help
Replies
7
Views
8K
  • Biology and Chemistry Homework Help
Replies
1
Views
1K
Replies
4
Views
2K
  • Biology and Chemistry Homework Help
Replies
1
Views
2K
Replies
1
Views
1K
Back
Top