A piece of granulated zinc was dropped into copper sulphate solution. After some time, the colour of the solution changed from:

Options

A. Colourless to blue
B. blue to colourless
C. Yellow to light green
D. blue to white

Explanation

To solve the question about the color change of copper sulfate solution when granulated zinc is added, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Initial Solution**:
- The initial solution is copper sulfate (CuSO4), which is known to be blue in color.

2. **Add Granulated Zinc**:
- When granulated zinc (Zn) is added to the copper sulfate solution, a chemical reaction occurs.

3. **Understand the Reaction**:
- Zinc is more reactive than copper. According to the reactivity series, zinc can displace copper from its compound.
- The reaction can be represented as:
\[ \text{Zn} + \text{CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu} \]
- In this reaction, zinc displaces copper from copper sulfate, forming zinc sulfate (ZnSO4) and releasing copper (Cu).

4. **Identify the Color of the Products**:
- Zinc sulfate (ZnSO4) is colorless in solution.
- Copper (Cu) is a solid and does not affect the color of the solution.

5. **Determine the Color Change**:
- Initially, the solution was blue due to the presence of copper sulfate.
- After the reaction, the solution becomes colorless because zinc sulfate is formed, which does not impart any color to the solution.

6. **Conclusion**:
- Therefore, the color of the solution changes from blue to colorless.

### Final Answer:
The correct option is **B: blue to colorless**.

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