Iodine is formed when potasium iodide reacts with:

Options

A. `ZnSO_(4)`
B. `CuSO_(4)`
C. `Cl_(2)`
D. `Br_(2)`

Answer

To determine which substances can react with potassium iodide (KI) to form iodine (I2), we can analyze the reactions step by step.

### Step 1: Understand the Reactants
- **Potassium Iodide (KI)**: This is a compound made up of potassium (K) and iodide (I-).
- **Iodine (I2)**: This is the diatomic form of iodine, which is what we are trying to produce.

### Step 2: Analyze Each Option
We will analyze the potential reactants provided in the question and see if they can produce iodine when reacted with potassium iodide.

#### Option A: Zinc Sulfate (ZnSO4)
- Reaction: KI + ZnSO4 → ZnI2 + K2SO4
- In this reaction, iodine (I2) is not produced. Therefore, this option does not yield iodine.

#### Option B: Copper(II) Sulfate (CuSO4)
- Reaction: 2 KI + CuSO4 → 2 CuI + I2 + K2SO4
- In this reaction, iodine (I2) is produced. Thus, this option yields iodine.

#### Option C: Chlorine (Cl2)
- Reaction: 2 KI + Cl2 → 2 KCl + I2
- In this reaction, iodine (I2) is produced. Thus, this option yields iodine.

#### Option D: Bromine (Br2)
- Reaction: 2 KI + Br2 → 2 KBr + I2
- In this reaction, iodine (I2) is produced. Thus, this option yields iodine.

### Step 3: Conclusion
From the analysis, we find that:
- **Option A** does not produce iodine.
- **Options B, C, and D** all produce iodine when reacted with potassium iodide.

### Final Answer
The substances that can react with potassium iodide to form iodine are:
- **B (CuSO4)**
- **C (Cl2)**
- **D (Br2)**