Starch iodide paper is used to test for the presence of

Options

A. Iodine
B. Iodide ion
C. Oxidising agnet
D. Reducing agent

Explanation

To solve the question regarding what starch iodide paper is used to test for, we can follow these steps:

### Step 1: Understand the Purpose of Starch Iodide Paper
Starch iodide paper is a chemical indicator that is primarily used to detect the presence of certain substances in a solution.

**Hint:** Think about what kind of reactions involve iodine and starch.

### Step 2: Identify the Options Given
The options provided are:
1. Iodine
2. Iodide
3. Oxidizing agent
4. Reducing agent

**Hint:** Consider the chemical properties of iodine and iodide, and how they interact with starch.

### Step 3: Recall the Reaction Involving Starch Iodide Paper
Starch iodide paper is known to change color in the presence of free iodine (I2). When iodine is present, it forms a complex with starch, resulting in a deep blue coloration.

**Hint:** Remember that starch reacts specifically with iodine and not with iodide ions.

### Step 4: Analyze the Role of Oxidizing Agents
Oxidizing agents, such as chlorine or nitrites, can oxidize iodide ions (I-) to iodine (I2). When starch iodide paper is used in the presence of these oxidizing agents, it indicates their presence by producing iodine, which then reacts with the starch.

**Hint:** Think about how oxidizing agents change the state of iodine in a solution.

### Step 5: Conclusion
Based on the above analysis, starch iodide paper is used to test for the presence of oxidizing agents. When these agents are present, they oxidize iodide ions to iodine, which can then be detected by the starch iodide paper.

**Final Answer:** Starch iodide paper is used to test for the presence of oxidizing agents.

### Summary of Steps:
1. Understand the purpose of starch iodide paper.
2. Identify the options given.
3. Recall the reaction involving starch iodide paper.
4. Analyze the role of oxidizing agents.
5. Conclude that starch iodide paper tests for oxidizing agents.