The solubility of iodine in water is increased by

Options

A. boiling the solution
B. adding `NaNO_3`
C. adding HI acid
D. addition of potassium iodide

Answer

To determine how to increase the solubility of iodine in water, we can analyze the given options step by step:

### Step 1: Understand the solubility of iodine in water
Iodine (I2) is a non-polar molecule and has low solubility in polar solvents like water. To increase its solubility, we need to introduce a method that can enhance its interaction with water.

### Step 2: Evaluate the options
1. **Boiling the solution**: Boiling may increase the kinetic energy of the molecules, but it does not fundamentally change the solubility of iodine in water. Therefore, this option is unlikely to increase solubility.

2. **Adding NaNO3 (sodium nitrate)**: Sodium nitrate is a soluble salt, but it does not interact with iodine in a way that would increase its solubility in water. This option is also unlikely to help.

3. **Adding HI (hydroiodic acid)**: Hydroiodic acid can provide iodide ions (I-) in solution. However, while it may increase the concentration of iodine in the solution, it does not directly enhance the solubility of iodine itself.

4. **Addition of potassium iodide (KI)**: Potassium iodide dissociates in water to give potassium ions (K+) and iodide ions (I-). The presence of iodide ions can form a complex with iodine, effectively increasing its solubility in water. This is the most effective method among the options provided.

### Step 3: Conclusion
Based on the analysis, the best option to increase the solubility of iodine in water is **the addition of potassium iodide (option D)**.

### Final Answer:
The solubility of iodine in water is increased by the addition of potassium iodide (KI).

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