Identify the statement which is correct for copper sulphate

Options

A. It reacts with `NaOH` and glucose to give `Cu_(2)O`
B. It reacts with KCl to give `Cu_(2)O`
C. It gives CuO on heating in air
D. It reacts with KI to give brown colouration

Answer

To identify the correct statement about copper sulfate (CuSO4), we will analyze the given options one by one.

### Step-by-Step Solution:

1. **Understanding Copper Sulfate Reactions:**
- Copper sulfate can react with various reagents, and we need to evaluate the reactions mentioned in the options.

2. **Option 1: Reacts with NaOH and glucose to give Cu2O.**
- When copper sulfate reacts with sodium hydroxide (NaOH) and glucose, it can indeed produce cuprous oxide (Cu2O). The reaction can be represented as:
\[ \text{CHO} + 2 \text{Cu}^{2+} + 5 \text{OH}^- \rightarrow \text{Cu}_2\text{O} + 3 \text{H}_2\text{O} \]
- This reaction results in a brick-red precipitate of cuprous oxide.
- **Conclusion:** This statement is correct.

3. **Option 2: Reacts with KCl to give Cu2O.**
- When copper sulfate reacts with potassium chloride (KCl), it does not produce cuprous oxide (Cu2O). Instead, it typically results in the formation of copper(II) chloride (CuCl2) and potassium sulfate (K2SO4).
- **Conclusion:** This statement is incorrect.

4. **Option 3: Gives CuO on heating in air.**
- When copper sulfate is heated strongly, it decomposes to form cupric oxide (CuO), sulfur dioxide (SO2), and oxygen (O2). The reaction can be represented as:
\[ 2 \text{CuSO}_4 \rightarrow 2 \text{CuO} + 2 \text{SO}_2 + \text{O}_2 \]
- **Conclusion:** This statement is correct.

5. **Option 4: Reacts with KI to give brown coloration.**
- Copper sulfate reacts with potassium iodide (KI) to produce cuprous iodide (CuI2) and iodine (I2). The liberation of iodine gives a brown coloration to the solution.
- The reaction can be represented as:
\[ \text{CuSO}_4 + 2 \text{KI} \rightarrow \text{Cu}_2\text{I}_2 + \text{I}_2 + 2 \text{K}_2\text{SO}_4 \]
- **Conclusion:** This statement is correct.

### Final Conclusion:
- The correct statements regarding copper sulfate are:
- Option 1: Reacts with NaOH and glucose to give Cu2O.
- Option 3: Gives CuO on heating in air.
- Option 4: Reacts with KI to give brown coloration.

### Summary of Correct Options:
- Options 1, 3, and 4 are correct.

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