`P_2 O_5` is used extensively as a/an

Options

A. Reducing agent
B. Oxidizing agent
C. Dehydrating agent
D. preservative

Explanation

To determine the primary use of \( P_2O_5 \), we can analyze its properties and applications in chemistry.

### Step 1: Identify the compound
The compound in question is \( P_2O_5 \), which is known as diphosphorus pentoxide.

### Step 2: Understand the properties of \( P_2O_5 \)
\( P_2O_5 \) is a white solid that is highly hygroscopic, meaning it readily absorbs moisture from the environment. This property is crucial in its applications.

### Step 3: Explore the potential uses
The question provides several options for the use of \( P_2O_5 \):
1. Reducing agent
2. Oxidizing agent
3. Dehydrating agent
4. Preservative

### Step 4: Analyze each option
- **Reducing agent**: Typically, reducing agents donate electrons in a chemical reaction. \( P_2O_5 \) does not primarily function in this capacity.
- **Oxidizing agent**: Oxidizing agents accept electrons. While phosphorus can act in this role, \( P_2O_5 \) is not primarily known for this.
- **Dehydrating agent**: \( P_2O_5 \) is well-known for its ability to remove water from substances, making it an effective dehydrating agent.
- **Preservative**: While some chemicals can act as preservatives, \( P_2O_5 \) is not typically classified as one.

### Step 5: Conclusion
Based on the properties and applications discussed, \( P_2O_5 \) is extensively used as a **dehydrating agent**.

### Final Answer
\( P_2O_5 \) is used extensively as a dehydrating agent.

---