When orthophosphoric acid is heated to `600^(@)C` the product formed is

Options

A. (a) `PH_(3)`
B. (b) `P_(2)O_(5)`
C. (c) `H_(3)PO_(3)`
D. (d) `HPO_(3)`

Explanation

To determine the product formed when orthophosphoric acid (H₃PO₄) is heated to 600°C, we can follow these steps:

### Step 1: Identify the compound
Orthophosphoric acid is represented by the chemical formula H₃PO₄.

### Step 2: Understand the thermal decomposition
When H₃PO₄ is heated, it undergoes thermal decomposition, which means it breaks down into different products depending on the temperature.

### Step 3: Review the decomposition process at different temperatures
- At **250°C**, H₃PO₄ decomposes to form **H₄P₂O₇** (pyrophosphoric acid) and water.
- At **316°C**, H₃PO₄ further decomposes to form **HPO₃** (metaphosphoric acid) and water.
- At **600°C**, H₃PO₄ decomposes to form **P₂O₅** (phosphorus pentoxide) and water.

### Step 4: Write the balanced equation for the decomposition at 600°C
The balanced equation for the decomposition of orthophosphoric acid at 600°C can be represented as:
\[ 4 \text{H}_3\text{PO}_4 \rightarrow 2 \text{P}_2\text{O}_5 + 2 \text{H}_2\text{O} \]

### Step 5: Identify the final product
From the decomposition reaction at 600°C, we can see that the product formed is **P₂O₅**.

### Conclusion
Thus, when orthophosphoric acid is heated to 600°C, the product formed is **P₂O₅** (phosphorus pentoxide).

### Answer:
The product formed when orthophosphoric acid is heated to 600°C is **P₂O₅** (option B).

---