Which of the following does NOT happen when a zinc rod is introduced into a solution of copper (ll) sulphate?
Electrons flow towards the zinc rod
The zinc rod dissolves
The temperature of the soil changes
The blue colour of the solution gradually disappears
Copper metal is deposited
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When a zinc rod is introduced into a solution of copper(II) sulphate, a displacement reaction occurs. Zinc is more reactive than copper, so it displaces the copper from the copper sulphate solution. The balanced chemical equation for this reaction is:
Zn+CuSO4→ZnSO4+Cu
Let’s evaluate each statement:
A. Electrons flow towards the zinc rod: This is not true. In the reaction, zinc is oxidized to zinc ions (loses electrons), and copper ions are reduced to copper metal (gains electrons). So, electrons actually flow away from the zinc rod.
B. The zinc rod dissolves: This is true. Zinc displaces copper from the copper sulphate solution, forming zinc sulphate and copper. The zinc rod dissolves in the process.
C. The temperature of the soil changes: This statement seems out of context as there’s no mention of soil in the reaction. If it’s meant to refer to the solution, it’s worth noting that the reaction is exothermic, meaning it releases heat and the temperature of the solution would increase.
D. The blue colour of the solution gradually disappears: This is true. Copper sulphate solution is blue, and as the zinc displaces the copper, forming zinc sulphate (which is colorless), the blue color of the solution fades.
E. Copper metal is deposited: This is true. As zinc displaces copper from the copper sulphate solution, copper metal is deposited.
So, the statement that does NOT happen when a zinc rod is introduced into a solution of copper(II) sulphate is A. Electrons flow towards the zinc rod.
Sir pls zinc is higher than copper in the activity series thus it is made the cathode in an electrolytic cell and electrons flow from the anode to cathode that is from copper to zinc.
Excuse me please. Zinc is higher than copper in the series and should act as the cathode and we all know electrons flow from the anode to cathode while current flows other wise. electrons can flow from copper to zinc na.
The correct answer is A. Electrons flow towards the zinc rod.
Here's why:
This is a classic example of a redox reaction (reduction-oxidation) where one metal displaces another from its salt solution. Here's what happens:
* Zinc is more reactive than copper: Zinc has a greater tendency to lose electrons than copper.
* Oxidation of Zinc: When the zinc rod is introduced into the copper (II) sulfate solution, zinc atoms lose electrons and become zinc ions (Zn²⁺). This is oxidation. These electrons are released into the solution.
* Reduction of Copper: Copper ions (Cu²⁺) in the solution gain these electrons and become copper atoms, which deposit on the zinc rod. This is reduction.
* Electron Flow: The electrons flow from the zinc rod towards the copper ions in the solution.
* Color Change: As copper ions are removed from the solution, the blue color of the copper (II) sulfate solution fades.
* Temperature Change: This reaction is exothermic, meaning it releases heat. So, the temperature of the solution will increase.
In summary:
* Zinc rod dissolves (B)
* The blue color disappears (D)
* Copper metal is deposited (E)
* The temperature changes (C)
Zn + CuSO4 --> Cu + ZnSO4
In essence Zinc displaces copper and releases two electrons 🤪
