Certain metals have the capacity to displace some metals from their salt solutions. These reactions are known as metal displacement reactions. A metal placed higher in activity series can displace the metal occupying lower position from aqueous solution of its salt or a more reactive metal can displace less reactive metal from its salt solution.
Q. Take aqueous solution of copper sulphate in one test tube and ferrous sulphate in another test tube. dip an iron nail in copper sulphate and copper wire in ferrous sulphate solution. mark the correct observation.

Options

A. Blue colour in first test tube changes to light green and green in the second test tube changes to blue
B. There is no reaction in both the test tubes.
C. Blue colour in first test tube changes to light green and no change in second test tube
D. Blue colour remains as such and green colour in second test tube changes to blue

Explanation

To solve the problem, we will analyze the reactions that occur when an iron nail is dipped in copper sulfate solution and when a copper wire is dipped in ferrous sulfate solution.

### Step-by-Step Solution:

1. **Identify the Solutions and Metals:**
- We have two test tubes:
- Test Tube 1: Copper sulfate (CuSO₄) solution
- Test Tube 2: Ferrous sulfate (FeSO₄) solution
- The metals involved are:
- Iron (Fe)
- Copper (Cu)

2. **Refer to the Reactivity Series:**
- The reactivity series ranks metals based on their ability to displace other metals from their compounds. In this case, iron is more reactive than copper.

3. **Reaction in Test Tube 1 (Iron Nail in Copper Sulfate):**
- When the iron nail is dipped in the copper sulfate solution, a displacement reaction occurs because iron is more reactive than copper.
- The reaction can be represented as:
\[ \text{Fe} + \text{CuSO}_4 \rightarrow \text{FeSO}_4 + \text{Cu} \]
- In this reaction, iron displaces copper from copper sulfate, forming ferrous sulfate (FeSO₄) and depositing copper.

4. **Observation in Test Tube 1:**
- The initial blue color of the copper sulfate solution will change to light green due to the formation of ferrous sulfate.
- Additionally, reddish-brown copper will be deposited at the bottom of the test tube.

5. **Reaction in Test Tube 2 (Copper Wire in Ferrous Sulfate):**
- When the copper wire is dipped in the ferrous sulfate solution, no reaction occurs because copper is less reactive than iron.
- Therefore, copper cannot displace iron from ferrous sulfate.

6. **Observation in Test Tube 2:**
- There will be no change in the ferrous sulfate solution, and it will remain unchanged.

7. **Final Observations:**
- In Test Tube 1, the solution changes from blue to light green, and copper is deposited.
- In Test Tube 2, there is no change.

### Conclusion:
- The correct observation is that the blue color in Test Tube 1 changes to light green, and there is no change in Test Tube 2.